631781631 has 12 divisors (see below), whose sum is σ = 982771608. Its totient is φ = 388788624.

The previous prime is 631781629. The next prime is 631781699. The reversal of 631781631 is 136187136.

631781631 is a `hidden beast` number, since 6 + 3 + 17 + 8 + 1 + 631 = 666.

It is not a de Polignac number, because 631781631 - 2¹ = 631781629 is a prime.

It is a super-2 number, since 2×631781631² = 798296058538040322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (631781611) 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 11 ways as a sum of consecutive naturals, for example, 2699805 + ... + 2700038.

It is an arithmetic number, because the mean of its divisors is an integer number (81897634).

Almost surely, 2^631781631 is an apocalyptic number.

631781631 is a deficient number, since it is larger than the sum of its proper divisors (350989977).

631781631 is a wasteful number, since it uses less digits than its factorization.

631781631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5399862 (or 5399859 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 631781631 is about 25135.2666785137. The cubic root of 631781631 is about 858.0692357776.

The spelling of 631781631 in words is "six hundred thirty-one million, seven hundred eighty-one thousand, six hundred thirty-one".