631451621 has 4 divisors (see below), whose sum is σ = 668595852. Its totient is φ = 594307392.

The previous prime is 631451609. The next prime is 631451629. The reversal of 631451621 is 126154136.

It is a happy number.

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 238857025 + 392594596 = 15455^2 + 19814^2 .

It is a cyclic number.

It is not a de Polignac number, because 631451621 - 2¹⁰ = 631450597 is a prime.

It is a super-2 number, since 2×631451621² = 797462299327055282, 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 (631451629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18572090 + ... + 18572123.

It is an arithmetic number, because the mean of its divisors is an integer number (167148963).

Almost surely, 2^631451621 is an apocalyptic number.

It is an amenable number.

631451621 is a deficient number, since it is larger than the sum of its proper divisors (37144231).

631451621 is a wasteful number, since it uses less digits than its factorization.

631451621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37144230.

The product of its digits is 4320, while the sum is 29.

The square root of 631451621 is about 25128.7011403296. The cubic root of 631451621 is about 857.9198061152.

The spelling of 631451621 in words is "six hundred thirty-one million, four hundred fifty-one thousand, six hundred twenty-one".