631621 has 4 divisors (see below), whose sum is σ = 637632. Its totient is φ = 625612.

The previous prime is 631619. The next prime is 631643. The reversal of 631621 is 126136.

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 631621 - 2¹ = 631619 is a prime.

It is a Duffinian number.

631621 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (631681) 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, 2845 + ... + 3058.

It is an arithmetic number, because the mean of its divisors is an integer number (159408).

2⁶³¹⁶²¹ is an apocalyptic number.

It is an amenable number.

631621 is a deficient number, since it is larger than the sum of its proper divisors (6011).

631621 is a wasteful number, since it uses less digits than its factorization.

631621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6010.

The product of its digits is 216, while the sum is 19.

The square root of 631621 is about 794.7458713325. The cubic root of 631621 is about 85.7996508010.

Adding to 631621 its reverse (126136), we get a palindrome (757757).

The spelling of 631621 in words is "six hundred thirty-one thousand, six hundred twenty-one".