645293531 has 16 divisors (see below), whose sum is σ = 689399424. Its totient is φ = 601903104.

The previous prime is 645293491. The next prime is 645293533. The reversal of 645293531 is 135392546.

It is a cyclic number.

It is not a de Polignac number, because 645293531 - 2²⁶ = 578184667 is a prime.

It is a super-2 number, since 2×645293531² = 832807482300895922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645293533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1758110 + ... + 1758476.

It is an arithmetic number, because the mean of its divisors is an integer number (43087464).

Almost surely, 2^645293531 is an apocalyptic number.

645293531 is a deficient number, since it is larger than the sum of its proper divisors (44105893).

645293531 is a wasteful number, since it uses less digits than its factorization.

645293531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1030.

The product of its digits is 97200, while the sum is 38.

The square root of 645293531 is about 25402.6284269955. The cubic root of 645293531 is about 864.1433067583.

The spelling of 645293531 in words is "six hundred forty-five million, two hundred ninety-three thousand, five hundred thirty-one".