631901 has 2 divisors, whose sum is σ = 631902. Its totient is φ = 631900.

The previous prime is 631889. The next prime is 631903. The reversal of 631901 is 109136.

631901 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 525625 + 106276 = 725^2 + 326^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-631901 is a prime.

It is a Sophie Germain prime.

Together with 631903, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315950 + 315951.

It is an arithmetic number, because the mean of its divisors is an integer number (315951).

2⁶³¹⁹⁰¹ is an apocalyptic number.

631901 is the 356-th centered decagonal number.

It is an amenable number.

631901 is a deficient number, since it is larger than the sum of its proper divisors (1).

631901 is an equidigital number, since it uses as much as digits as its factorization.

631901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 20.

The square root of 631901 is about 794.9220087531. The cubic root of 631901 is about 85.8123273656.

The spelling of 631901 in words is "six hundred thirty-one thousand, nine hundred one".