64373731521 has 32 divisors (see below), whose sum is σ = 95292192768. Its totient is φ = 38326875840.

The previous prime is 64373731501. The next prime is 64373731531. The reversal of 64373731521 is 12513737346.

It is a happy number.

It is not a de Polignac number, because 64373731521 - 2¹⁰ = 64373730497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64373731501) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 771771 + ... + 851103.

It is an arithmetic number, because the mean of its divisors is an integer number (2977881024).

Almost surely, 2^64373731521 is an apocalyptic number.

It is an amenable number.

64373731521 is a deficient number, since it is larger than the sum of its proper divisors (30918461247).

64373731521 is a wasteful number, since it uses less digits than its factorization.

64373731521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79781.

The product of its digits is 317520, while the sum is 42.

The spelling of 64373731521 in words is "sixty-four billion, three hundred seventy-three million, seven hundred thirty-one thousand, five hundred twenty-one".