631861709 has 2 divisors, whose sum is σ = 631861710. Its totient is φ = 631861708.

The previous prime is 631861697. The next prime is 631861717. The reversal of 631861709 is 907168136.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 490489609 + 141372100 = 22147^2 + 11890^2 .

It is a cyclic number.

It is not a de Polignac number, because 631861709 - 2⁴ = 631861693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631861759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315930854 + 315930855.

It is an arithmetic number, because the mean of its divisors is an integer number (315930855).

Almost surely, 2^631861709 is an apocalyptic number.

It is an amenable number.

631861709 is a deficient number, since it is larger than the sum of its proper divisors (1).

631861709 is an equidigital number, since it uses as much as digits as its factorization.

631861709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 631861709 is about 25136.8595691666. The cubic root of 631861709 is about 858.1054875256.

The spelling of 631861709 in words is "six hundred thirty-one million, eight hundred sixty-one thousand, seven hundred nine".