645066631 has 16 divisors (see below), whose sum is σ = 727999488. Its totient is φ = 566265600.

The previous prime is 645066629. The next prime is 645066661. The reversal of 645066631 is 136660546.

It is a cyclic number.

It is not a de Polignac number, because 645066631 - 2¹ = 645066629 is a prime.

It is a super-2 number, since 2×645066631² = 832221916859380322, 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 (645066661) 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, 176535 + ... + 180151.

It is an arithmetic number, because the mean of its divisors is an integer number (45499968).

Almost surely, 2^645066631 is an apocalyptic number.

645066631 is a deficient number, since it is larger than the sum of its proper divisors (82932857).

645066631 is a wasteful number, since it uses less digits than its factorization.

645066631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4182.

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 645066631 is about 25398.1619610554. The cubic root of 645066631 is about 864.0420106852.

The spelling of 645066631 in words is "six hundred forty-five million, sixty-six thousand, six hundred thirty-one".