631509231 has 4 divisors (see below), whose sum is σ = 842012312. Its totient is φ = 421006152.

The previous prime is 631509227. The next prime is 631509247. The reversal of 631509231 is 132905136.

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

It is not a de Polignac number, because 631509231 - 2² = 631509227 is a prime.

It is a super-2 number, since 2×631509231² = 797607817676422722, 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 (631509731) 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, 105251536 + ... + 105251541.

It is an arithmetic number, because the mean of its divisors is an integer number (210503078).

Almost surely, 2^631509231 is an apocalyptic number.

631509231 is a deficient number, since it is larger than the sum of its proper divisors (210503081).

631509231 is a wasteful number, since it uses less digits than its factorization.

631509231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210503080.

The product of its (nonzero) digits is 4860, while the sum is 30.

The square root of 631509231 is about 25129.8474129868. The cubic root of 631509231 is about 857.9458958717.

The spelling of 631509231 in words is "six hundred thirty-one million, five hundred nine thousand, two hundred thirty-one".