645031031 has 4 divisors (see below), whose sum is σ = 649955064. Its totient is φ = 640107000.

The previous prime is 645030973. The next prime is 645031039. The reversal of 645031031 is 130130546.

It is a happy number.

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 645031031 - 2¹⁰ = 645030007 is a prime.

It is a super-2 number, since 2×645031031² = 832130061905845922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645030988 and 645031006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645031039) 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, 2461820 + ... + 2462081.

It is an arithmetic number, because the mean of its divisors is an integer number (162488766).

Almost surely, 2^645031031 is an apocalyptic number.

645031031 is a deficient number, since it is larger than the sum of its proper divisors (4924033).

645031031 is a wasteful number, since it uses less digits than its factorization.

645031031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4924032.

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 645031031 is about 25397.4611132688. The cubic root of 645031031 is about 864.0261154479.

Adding to 645031031 its reverse (130130546), we get a palindrome (775161577).

The spelling of 645031031 in words is "six hundred forty-five million, thirty-one thousand, thirty-one".