63995781 has 16 divisors (see below), whose sum is σ = 90104000. Its totient is φ = 40290048.

The previous prime is 63995777. The next prime is 63995791. The reversal of 63995781 is 18759936.

It is not a de Polignac number, because 63995781 - 2² = 63995777 is a prime.

It is a super-2 number, since 2×63995781² = 8190919971599922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 63995781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63995761) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18285 + ... + 21501.

It is an arithmetic number, because the mean of its divisors is an integer number (5631500).

Almost surely, 2^63995781 is an apocalyptic number.

It is an amenable number.

63995781 is a deficient number, since it is larger than the sum of its proper divisors (26108219).

63995781 is a wasteful number, since it uses less digits than its factorization.

63995781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3588.

The product of its digits is 408240, while the sum is 48.

The square root of 63995781 is about 7999.7363081542. The cubic root of 63995781 is about 399.9912102235.

The spelling of 63995781 in words is "sixty-three million, nine hundred ninety-five thousand, seven hundred eighty-one".