55637921 has 4 divisors (see below), whose sum is σ = 57556500. Its totient is φ = 53719344.

The previous prime is 55637873. The next prime is 55637951. The reversal of 55637921 is 12973655.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 47458321 + 8179600 = 6889^2 + 2860^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55637921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55637951) 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, 959246 + ... + 959303.

It is an arithmetic number, because the mean of its divisors is an integer number (14389125).

Almost surely, 2^55637921 is an apocalyptic number.

It is an amenable number.

55637921 is a deficient number, since it is larger than the sum of its proper divisors (1918579).

55637921 is a wasteful number, since it uses less digits than its factorization.

55637921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1918578.

The product of its digits is 56700, while the sum is 38.

The square root of 55637921 is about 7459.0831205987. The cubic root of 55637921 is about 381.7598908660.

The spelling of 55637921 in words is "fifty-five million, six hundred thirty-seven thousand, nine hundred twenty-one".