631217664 has 320 divisors, whose sum is σ = 2333422080. Its totient is φ = 163676160.

The previous prime is 631217659. The next prime is 631217723. The reversal of 631217664 is 466712136.

It is a happy number.

631217664 is a `hidden beast` number, since 631 + 2 + 17 + 6 + 6 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1064152 + ... + 1064744.

It is an arithmetic number, because the mean of its divisors is an integer number (7291944).

Almost surely, 2^631217664 is an apocalyptic number.

631217664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 631217664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1166711040).

631217664 is an abundant number, since it is smaller than the sum of its proper divisors (1702204416).

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

631217664 is a wasteful number, since it uses less digits than its factorization.

631217664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638 (or 616 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 631217664 is about 25124.0455341094. The cubic root of 631217664 is about 857.8138380403.

The spelling of 631217664 in words is "six hundred thirty-one million, two hundred seventeen thousand, six hundred sixty-four".