64607991 has 16 divisors (see below), whose sum is σ = 99373824. Its totient is φ = 36572544.

The previous prime is 64607987. The next prime is 64608023. The reversal of 64607991 is 19970646.

It is not a de Polignac number, because 64607991 - 2² = 64607987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64607951) 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 15 ways as a sum of consecutive naturals, for example, 12130 + ... + 16623.

It is an arithmetic number, because the mean of its divisors is an integer number (6210864).

Almost surely, 2^64607991 is an apocalyptic number.

64607991 is a deficient number, since it is larger than the sum of its proper divisors (34765833).

64607991 is a wasteful number, since it uses less digits than its factorization.

64607991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28870.

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 64607991 is about 8037.9096163119. The cubic root of 64607991 is about 401.2626579600.

The spelling of 64607991 in words is "sixty-four million, six hundred seven thousand, nine hundred ninety-one".