64757875621 has 4 divisors (see below), whose sum is σ = 66337336044. Its totient is φ = 63178415200.

The previous prime is 64757875573. The next prime is 64757875639. The reversal of 64757875621 is 12657875746.

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 28035818721 + 36722056900 = 167439^2 + 191630^2 .

It is a cyclic number.

It is not a de Polignac number, because 64757875621 - 2²³ = 64749487013 is a prime.

It is a super-2 number, since 2×64757875621² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64757875681) 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, 789730150 + ... + 789730231.

It is an arithmetic number, because the mean of its divisors is an integer number (16584334011).

Almost surely, 2^64757875621 is an apocalyptic number.

It is an amenable number.

64757875621 is a deficient number, since it is larger than the sum of its proper divisors (1579460423).

64757875621 is a wasteful number, since it uses less digits than its factorization.

64757875621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1579460422.

The product of its digits is 19756800, while the sum is 58.

The spelling of 64757875621 in words is "sixty-four billion, seven hundred fifty-seven million, eight hundred seventy-five thousand, six hundred twenty-one".