64396987261 has 4 divisors (see below), whose sum is σ = 67786302400. Its totient is φ = 61007672124.

The previous prime is 64396987247. The next prime is 64396987267. The reversal of 64396987261 is 16278969346.

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 64396987261 - 2⁵ = 64396987229 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64396987261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64396987267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1694657541 + ... + 1694657578.

It is an arithmetic number, because the mean of its divisors is an integer number (16946575600).

Almost surely, 2^64396987261 is an apocalyptic number.

It is an amenable number.

64396987261 is a deficient number, since it is larger than the sum of its proper divisors (3389315139).

64396987261 is a wasteful number, since it uses less digits than its factorization.

64396987261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3389315138.

The product of its digits is 23514624, while the sum is 61.

The spelling of 64396987261 in words is "sixty-four billion, three hundred ninety-six million, nine hundred eighty-seven thousand, two hundred sixty-one".