64711991 has 2 divisors, whose sum is σ = 64711992. Its totient is φ = 64711990.

The previous prime is 64711987. The next prime is 64712003. The reversal of 64711991 is 19911746.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 64711991 - 2² = 64711987 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64711931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32355995 + 32355996.

It is an arithmetic number, because the mean of its divisors is an integer number (32355996).

Almost surely, 2^64711991 is an apocalyptic number.

64711991 is a deficient number, since it is larger than the sum of its proper divisors (1).

64711991 is an equidigital number, since it uses as much as digits as its factorization.

64711991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13608, while the sum is 38.

The square root of 64711991 is about 8044.3763586744. The cubic root of 64711991 is about 401.4778477739.

The spelling of 64711991 in words is "sixty-four million, seven hundred eleven thousand, nine hundred ninety-one".