631021 has 4 divisors (see below), whose sum is σ = 632700. Its totient is φ = 629344.

The previous prime is 631013. The next prime is 631039. The reversal of 631021 is 120136.

631021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45796 + 585225 = 214^2 + 765^2 .

It is a cyclic number.

It is not a de Polignac number, because 631021 - 2³ = 631013 is a prime.

It is a Duffinian number.

631021 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 630992 and 631010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (631061) 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, 15 + ... + 1123.

It is an arithmetic number, because the mean of its divisors is an integer number (158175).

2⁶³¹⁰²¹ is an apocalyptic number.

It is an amenable number.

631021 is a deficient number, since it is larger than the sum of its proper divisors (1679).

631021 is a wasteful number, since it uses less digits than its factorization.

631021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1678.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 631021 is about 794.3683024895. The cubic root of 631021 is about 85.7724741134.

Adding to 631021 its reverse (120136), we get a palindrome (751157).

The spelling of 631021 in words is "six hundred thirty-one thousand, twenty-one".