63999956 has 6 divisors (see below), whose sum is σ = 111999930. Its totient is φ = 31999976.

The previous prime is 63999937. The next prime is 63999967. The reversal of 63999956 is 65999936.

It can be written as a sum of positive squares in only one way, i.e., 39891856 + 24108100 = 6316^2 + 4910^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7999991 + ... + 7999998.

It is an arithmetic number, because the mean of its divisors is an integer number (18666655).

Almost surely, 2^63999956 is an apocalyptic number.

It is an amenable number.

63999956 is a deficient number, since it is larger than the sum of its proper divisors (47999974).

63999956 is a wasteful number, since it uses less digits than its factorization.

63999956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15999993 (or 15999991 counting only the distinct ones).

The product of its digits is 3542940, while the sum is 56.

The square root of 63999956 is about 7999.9972499995. The cubic root of 63999956 is about 399.9999083333. Note that the first 4 decimals are identical.

The spelling of 63999956 in words is "sixty-three million, nine hundred ninety-nine thousand, nine hundred fifty-six".