64555431621 has 4 divisors (see below), whose sum is σ = 86073908832. Its totient is φ = 43036954412.

The previous prime is 64555431607. The next prime is 64555431667. The reversal of 64555431621 is 12613455546.

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 64555431621 - 2⁶ = 64555431557 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64555435621) 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, 10759238601 + ... + 10759238606.

It is an arithmetic number, because the mean of its divisors is an integer number (21518477208).

Almost surely, 2^64555431621 is an apocalyptic number.

It is an amenable number.

64555431621 is a deficient number, since it is larger than the sum of its proper divisors (21518477211).

64555431621 is a wasteful number, since it uses less digits than its factorization.

64555431621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21518477210.

The product of its digits is 432000, while the sum is 42.

The spelling of 64555431621 in words is "sixty-four billion, five hundred fifty-five million, four hundred thirty-one thousand, six hundred twenty-one".