64718991 has 6 divisors (see below), whose sum is σ = 93483000. Its totient is φ = 43145988.

The previous prime is 64718911. The next prime is 64718993. The reversal of 64718991 is 19981746.

It is a happy number.

It is not a de Polignac number, because 64718991 - 2¹⁴ = 64702607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64718993) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3595491 + ... + 3595508.

It is an arithmetic number, because the mean of its divisors is an integer number (15580500).

Almost surely, 2^64718991 is an apocalyptic number.

64718991 is a deficient number, since it is larger than the sum of its proper divisors (28764009).

64718991 is a wasteful number, since it uses less digits than its factorization.

64718991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7191005 (or 7191002 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 64718991 is about 8044.8114334644. The cubic root of 64718991 is about 401.4923234198.

The spelling of 64718991 in words is "sixty-four million, seven hundred eighteen thousand, nine hundred ninety-one".