63978881 has 4 divisors (see below), whose sum is σ = 64880064. Its totient is φ = 63077700.

The previous prime is 63978857. The next prime is 63978899. The reversal of 63978881 is 18887936.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-63978881 is a prime.

It is a super-2 number, since 2×63978881² = 8186594428024322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63978821) 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, 450485 + ... + 450626.

It is an arithmetic number, because the mean of its divisors is an integer number (16220016).

Almost surely, 2^63978881 is an apocalyptic number.

It is an amenable number.

63978881 is a deficient number, since it is larger than the sum of its proper divisors (901183).

63978881 is an equidigital number, since it uses as much as digits as its factorization.

63978881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 901182.

The product of its digits is 580608, while the sum is 50.

The square root of 63978881 is about 7998.6799535923. The cubic root of 63978881 is about 399.9559972429.

The spelling of 63978881 in words is "sixty-three million, nine hundred seventy-eight thousand, eight hundred eighty-one".