1621616 has 20 divisors (see below), whose sum is σ = 3216312. Its totient is φ = 791616.

The previous prime is 1621597. The next prime is 1621619. The reversal of 1621616 is 6161261.

It is a junction number, because it is equal to n+sod(n) for n = 1621591 and 1621600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621619) 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 3 ways as a sum of consecutive naturals, for example, 491 + ... + 1866.

2^1621616 is an apocalyptic number.

1621616 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1621616 is a deficient number, since it is larger than the sum of its proper divisors (1594696).

1621616 is a wasteful number, since it uses less digits than its factorization.

1621616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2408 (or 2402 counting only the distinct ones).

The product of its digits is 432, while the sum is 23.

The square root of 1621616 is about 1273.4268726550. The cubic root of 1621616 is about 117.4850682701.

Adding to 1621616 its reverse (6161261), we get a palindrome (7782877).

The spelling of 1621616 in words is "one million, six hundred twenty-one thousand, six hundred sixteen".