631749640 has 16 divisors (see below), whose sum is σ = 1421436780. Its totient is φ = 252699840.

The previous prime is 631749637. The next prime is 631749641. The reversal of 631749640 is 46947136.

It can be written as a sum of positive squares in 2 ways, for example, as 631717956 + 31684 = 25134^2 + 178^2 .

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 15793741 = 631749640 / (6 + 3 + 1 + 7 + 4 + 9 + 6 + 4 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 631749593 and 631749602.

It is not an unprimeable number, because it can be changed into a prime (631749641) 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, 7896831 + ... + 7896910.

Almost surely, 2^631749640 is an apocalyptic number.

It is an amenable number.

631749640 is an abundant number, since it is smaller than the sum of its proper divisors (789687140).

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

631749640 is a wasteful number, since it uses less digits than its factorization.

631749640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15793752 (or 15793748 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 40.

The square root of 631749640 is about 25134.6302936805. The cubic root of 631749640 is about 858.0547524208.

The spelling of 631749640 in words is "six hundred thirty-one million, seven hundred forty-nine thousand, six hundred forty".