645640545 has 16 divisors (see below), whose sum is σ = 1126936512. Its totient is φ = 313037760.

The previous prime is 645640519. The next prime is 645640553. The reversal of 645640545 is 545046546.

It is not a de Polignac number, because 645640545 - 2¹² = 645636449 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1956322 + ... + 1956651.

It is an arithmetic number, because the mean of its divisors is an integer number (70433532).

Almost surely, 2^645640545 is an apocalyptic number.

It is an amenable number.

645640545 is a deficient number, since it is larger than the sum of its proper divisors (481295967).

645640545 is a wasteful number, since it uses less digits than its factorization.

645640545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3912992.

The product of its (nonzero) digits is 288000, while the sum is 39.

The square root of 645640545 is about 25409.4577864228. The cubic root of 645640545 is about 864.2981799926.

The spelling of 645640545 in words is "six hundred forty-five million, six hundred forty thousand, five hundred forty-five".