645633131 has 24 divisors (see below), whose sum is σ = 768857040. Its totient is φ = 538528320.

The previous prime is 645633127. The next prime is 645633137. The reversal of 645633131 is 131336546.

It is not a de Polignac number, because 645633131 - 2² = 645633127 is a prime.

It is a super-2 number, since 2×645633131² = 833684279689726322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645633137) 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 23 ways as a sum of consecutive naturals, for example, 280421 + ... + 282713.

It is an arithmetic number, because the mean of its divisors is an integer number (32035710).

Almost surely, 2^645633131 is an apocalyptic number.

645633131 is a deficient number, since it is larger than the sum of its proper divisors (123223909).

645633131 is a wasteful number, since it uses less digits than its factorization.

645633131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2507 (or 2496 counting only the distinct ones).

The product of its digits is 19440, while the sum is 32.

The square root of 645633131 is about 25409.3118954449. The cubic root of 645633131 is about 864.2948716857.

Adding to 645633131 its reverse (131336546), we get a palindrome (776969677).

The spelling of 645633131 in words is "six hundred forty-five million, six hundred thirty-three thousand, one hundred thirty-one".