55556621 has 4 divisors (see below), whose sum is σ = 55836000. Its totient is φ = 55277244.

The previous prime is 55556617. The next prime is 55556623. The reversal of 55556621 is 12665555.

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.

It is a cyclic number.

It is not a de Polignac number, because 55556621 - 2² = 55556617 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55556623) 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, 139391 + ... + 139788.

It is an arithmetic number, because the mean of its divisors is an integer number (13959000).

Almost surely, 2^55556621 is an apocalyptic number.

It is an amenable number.

55556621 is a deficient number, since it is larger than the sum of its proper divisors (279379).

55556621 is a wasteful number, since it uses less digits than its factorization.

55556621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279378.

The product of its digits is 45000, while the sum is 35.

The square root of 55556621 is about 7453.6313968427. The cubic root of 55556621 is about 381.5738534277.

The spelling of 55556621 in words is "fifty-five million, five hundred fifty-six thousand, six hundred twenty-one".