64697639409 has 40 divisors (see below), whose sum is σ = 105507381672. Its totient is φ = 39268488960.

The previous prime is 64697639401. The next prime is 64697639443. The reversal of 64697639409 is 90493679646.

It can be written as a sum of positive squares in 4 ways, for example, as 246647025 + 64450992384 = 15705^2 + 253872^2 .

It is not a de Polignac number, because 64697639409 - 2³ = 64697639401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64697639401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 343962 + ... + 497699.

Almost surely, 2^64697639409 is an apocalyptic number.

It is an amenable number.

64697639409 is a deficient number, since it is larger than the sum of its proper divisors (40809742263).

64697639409 is a wasteful number, since it uses less digits than its factorization.

64697639409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 841759 (or 841750 counting only the distinct ones).

The product of its (nonzero) digits is 52907904, while the sum is 63.

The spelling of 64697639409 in words is "sixty-four billion, six hundred ninety-seven million, six hundred thirty-nine thousand, four hundred nine".