1681551 has 12 divisors (see below), whose sum is σ = 2441712. Its totient is φ = 1115136.

The previous prime is 1681541. The next prime is 1681571. The reversal of 1681551 is 1551861.

It is not a de Polignac number, because 1681551 - 2⁷ = 1681423 is a prime.

It is a super-2 number, since 2×1681551² = 5655227531202, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1950 + ... + 2676.

It is an arithmetic number, because the mean of its divisors is an integer number (203476).

2^1681551 is an apocalyptic number.

1681551 is a deficient number, since it is larger than the sum of its proper divisors (760161).

1681551 is a wasteful number, since it uses less digits than its factorization.

1681551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 990 (or 987 counting only the distinct ones).

The product of its digits is 1200, while the sum is 27.

The square root of 1681551 is about 1296.7463128924. The cubic root of 1681551 is about 118.9150112273.

The spelling of 1681551 in words is "one million, six hundred eighty-one thousand, five hundred fifty-one".