631720978 has 16 divisors (see below), whose sum is σ = 1120294080. Its totient is φ = 261401616.

The previous prime is 631720933. The next prime is 631720981. The reversal of 631720978 is 879027136.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 777576 + ... + 778387.

It is an arithmetic number, because the mean of its divisors is an integer number (70018380).

Almost surely, 2^631720978 is an apocalyptic number.

631720978 is a deficient number, since it is larger than the sum of its proper divisors (488573102).

631720978 is a wasteful number, since it uses less digits than its factorization.

631720978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556001.

The product of its (nonzero) digits is 127008, while the sum is 43.

The square root of 631720978 is about 25134.0601176969. The cubic root of 631720978 is about 858.0417757944.

The spelling of 631720978 in words is "six hundred thirty-one million, seven hundred twenty thousand, nine hundred seventy-eight".