64017991 has 2 divisors, whose sum is σ = 64017992. Its totient is φ = 64017990.

The previous prime is 64017959. The next prime is 64018037. The reversal of 64017991 is 19971046.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 64017991 - 2⁵ = 64017959 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 64017991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64017911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32008995 + 32008996.

It is an arithmetic number, because the mean of its divisors is an integer number (32008996).

Almost surely, 2^64017991 is an apocalyptic number.

64017991 is a deficient number, since it is larger than the sum of its proper divisors (1).

64017991 is an equidigital number, since it uses as much as digits as its factorization.

64017991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13608, while the sum is 37.

The square root of 64017991 is about 8001.1243584886. The cubic root of 64017991 is about 400.0374777384.

The spelling of 64017991 in words is "sixty-four million, seventeen thousand, nine hundred ninety-one".