1551616 has 72 divisors (see below), whose sum is σ = 3679200. Its totient is φ = 645120.

The previous prime is 1551601. The next prime is 1551617. The reversal of 1551616 is 6161551.

1551616 = T₁₈₃ + T₁₈₄ + ... + T₂₄₈.

It is a super-2 number, since 2×1551616² = 4815024422912, which contains 22 as substring.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

Its product of digits (900) is a multiple of the sum of its prime factors (75).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1551617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53490 + ... + 53518.

It is an arithmetic number, because the mean of its divisors is an integer number (51100).

2^1551616 is an apocalyptic number.

1551616 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1551616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1839600).

1551616 is an abundant number, since it is smaller than the sum of its proper divisors (2127584).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1551616 is a wasteful number, since it uses less digits than its factorization.

1551616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75 (or 61 counting only the distinct ones).

The product of its digits is 900, while the sum is 25.

The square root of 1551616 is about 1245.6387919457. The cubic root of 1551616 is about 115.7696578530.

Adding to 1551616 its product of digits (900), we get a square (1552516 = 1246²).

It can be divided in two parts, 155 and 1616, that added together give a palindrome (1771).

The spelling of 1551616 in words is "one million, five hundred fifty-one thousand, six hundred sixteen".