631381 has 4 divisors (see below), whose sum is σ = 639072. Its totient is φ = 623692.

The previous prime is 631361. The next prime is 631387. The reversal of 631381 is 183136.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 631381 - 2¹⁵ = 598613 is a prime.

It is a super-2 number, since 2×631381² = 797283934322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (631387) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3721 + ... + 3886.

It is an arithmetic number, because the mean of its divisors is an integer number (159768).

2⁶³¹³⁸¹ is an apocalyptic number.

It is an amenable number.

631381 is a deficient number, since it is larger than the sum of its proper divisors (7691).

631381 is an equidigital number, since it uses as much as digits as its factorization.

631381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7690.

The product of its digits is 432, while the sum is 22.

The square root of 631381 is about 794.5948653245. The cubic root of 631381 is about 85.7887821921.

It can be divided in two parts, 63 and 1381, that added together give a square (1444 = 38²).

The spelling of 631381 in words is "six hundred thirty-one thousand, three hundred eighty-one".