63959991 has 4 divisors (see below), whose sum is σ = 85279992. Its totient is φ = 42639992.

The previous prime is 63959989. The next prime is 63960011. The reversal of 63959991 is 19995936.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 63959991 - 2¹ = 63959989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63959911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10659996 + ... + 10660001.

It is an arithmetic number, because the mean of its divisors is an integer number (21319998).

Almost surely, 2^63959991 is an apocalyptic number.

63959991 is a deficient number, since it is larger than the sum of its proper divisors (21320001).

63959991 is a wasteful number, since it uses less digits than its factorization.

63959991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21320000.

The product of its digits is 590490, while the sum is 51.

The square root of 63959991 is about 7997.4990465770. The cubic root of 63959991 is about 399.9166305417.

The spelling of 63959991 in words is "sixty-three million, nine hundred fifty-nine thousand, nine hundred ninety-one".