55616521 has 4 divisors (see below), whose sum is σ = 55648000. Its totient is φ = 55585044.

The previous prime is 55616479. The next prime is 55616549. The reversal of 55616521 is 12561655.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12561655 = 5 ⋅2512331.

It is a cyclic number.

It is not a de Polignac number, because 55616521 - 2¹¹ = 55614473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55616621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12921 + ... + 16678.

It is an arithmetic number, because the mean of its divisors is an integer number (13912000).

Almost surely, 2^55616521 is an apocalyptic number.

It is an amenable number.

55616521 is a deficient number, since it is larger than the sum of its proper divisors (31479).

55616521 is a wasteful number, since it uses less digits than its factorization.

55616521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31478.

The product of its digits is 9000, while the sum is 31.

The square root of 55616521 is about 7457.6484899732. The cubic root of 55616521 is about 381.7109391848.

The spelling of 55616521 in words is "fifty-five million, six hundred sixteen thousand, five hundred twenty-one".