631617978 has 16 divisors (see below), whose sum is σ = 1282091040. Its totient is φ = 207396816.

The previous prime is 631617977. The next prime is 631617989. The reversal of 631617978 is 879716136.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (631617971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 785193 + ... + 785996.

It is an arithmetic number, because the mean of its divisors is an integer number (80130690).

Almost surely, 2^631617978 is an apocalyptic number.

631617978 is an abundant number, since it is smaller than the sum of its proper divisors (650473062).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

631617978 is a wasteful number, since it uses less digits than its factorization.

631617978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1571261.

The product of its digits is 381024, while the sum is 48.

The square root of 631617978 is about 25132.0110218025. The cubic root of 631617978 is about 857.9951396424.

The spelling of 631617978 in words is "six hundred thirty-one million, six hundred seventeen thousand, nine hundred seventy-eight".