64343902921 has 3 divisors (see below), whose sum is σ = 64344156583. Its totient is φ = 64343649260.

The previous prime is 64343902913. The next prime is 64343902951. The reversal of 64343902921 is 12920934346.

The square root of 64343902921 is 253661.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 35396283321 + 28947619600 = 188139^2 + 170140^2 .

It is not a de Polignac number, because 64343902921 - 2³ = 64343902913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64343902951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 126831 + ... + 380491.

Almost surely, 2^64343902921 is an apocalyptic number.

64343902921 is the 253661-st square number.

64343902921 is the 126831-st centered octagonal number.

It is an amenable number.

64343902921 is a deficient number, since it is larger than the sum of its proper divisors (253662).

64343902921 is an frugal number, since it uses more digits than its factorization.

64343902921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507322 (or 253661 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 43.

The spelling of 64343902921 in words is "sixty-four billion, three hundred forty-three million, nine hundred two thousand, nine hundred twenty-one".