631781629 has 2 divisors, whose sum is σ = 631781630. Its totient is φ = 631781628.

The previous prime is 631781627. The next prime is 631781699. The reversal of 631781629 is 926187136.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 424277604 + 207504025 = 20598^2 + 14405^2 .

It is a cyclic number.

It is not a de Polignac number, because 631781629 - 2¹ = 631781627 is a prime.

Together with 631781627, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631781627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315890814 + 315890815.

It is an arithmetic number, because the mean of its divisors is an integer number (315890815).

Almost surely, 2^631781629 is an apocalyptic number.

It is an amenable number.

631781629 is a deficient number, since it is larger than the sum of its proper divisors (1).

631781629 is an equidigital number, since it uses as much as digits as its factorization.

631781629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 43.

The square root of 631781629 is about 25135.2666387289. The cubic root of 631781629 is about 858.0692348722.

The spelling of 631781629 in words is "six hundred thirty-one million, seven hundred eighty-one thousand, six hundred twenty-nine".