55640621 has 4 divisors (see below), whose sum is σ = 56824512. Its totient is φ = 54456732.

The previous prime is 55640617. The next prime is 55640653. The reversal of 55640621 is 12604655.

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 55640621 - 2² = 55640617 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 (55640671) 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, 591875 + ... + 591968.

It is an arithmetic number, because the mean of its divisors is an integer number (14206128).

Almost surely, 2^55640621 is an apocalyptic number.

It is an amenable number.

55640621 is a deficient number, since it is larger than the sum of its proper divisors (1183891).

55640621 is a wasteful number, since it uses less digits than its factorization.

55640621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1183890.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 55640621 is about 7459.2641057949. The cubic root of 55640621 is about 381.7660661209.

The spelling of 55640621 in words is "fifty-five million, six hundred forty thousand, six hundred twenty-one".