645232031 has 4 divisors (see below), whose sum is σ = 647334072. Its totient is φ = 643129992.

The previous prime is 645231989. The next prime is 645232037. The reversal of 645232031 is 130232546.

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

It is a cyclic number.

It is not a de Polignac number, because 645232031 - 2⁶ = 645231967 is a prime.

It is a super-2 number, since 2×645232031² = 832648747656769922, 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 (645232037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1050560 + ... + 1051173.

It is an arithmetic number, because the mean of its divisors is an integer number (161833518).

Almost surely, 2^645232031 is an apocalyptic number.

645232031 is a deficient number, since it is larger than the sum of its proper divisors (2102041).

645232031 is a wasteful number, since it uses less digits than its factorization.

645232031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2102040.

The product of its (nonzero) digits is 4320, while the sum is 26.

The square root of 645232031 is about 25401.4178934956. The cubic root of 645232031 is about 864.1158533596.

Adding to 645232031 its reverse (130232546), we get a palindrome (775464577).

It can be divided in two parts, 6452 and 32031, that added together give a palindrome (38483).

The spelling of 645232031 in words is "six hundred forty-five million, two hundred thirty-two thousand, thirty-one".