631964581 has 2 divisors, whose sum is σ = 631964582. Its totient is φ = 631964580.

The previous prime is 631964513. The next prime is 631964617. The reversal of 631964581 is 185469136.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 623750625 + 8213956 = 24975^2 + 2866^2 .

It is a cyclic number.

It is not a de Polignac number, because 631964581 - 2¹³ = 631956389 is a prime.

It is a super-2 number, since 2×631964581² = 798758463277011122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631964981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315982290 + 315982291.

It is an arithmetic number, because the mean of its divisors is an integer number (315982291).

Almost surely, 2^631964581 is an apocalyptic number.

It is an amenable number.

631964581 is a deficient number, since it is larger than the sum of its proper divisors (1).

631964581 is an equidigital number, since it uses as much as digits as its factorization.

631964581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520, while the sum is 43.

The square root of 631964581 is about 25138.9057239968. The cubic root of 631964581 is about 858.1520537474.

The spelling of 631964581 in words is "six hundred thirty-one million, nine hundred sixty-four thousand, five hundred eighty-one".