645583887 has 36 divisors (see below), whose sum is σ = 1013168520. Its totient is φ = 395942976.

The previous prime is 645583769. The next prime is 645583889. The reversal of 645583887 is 788385546.

645583887 is a `hidden beast` number, since 6 + 4 + 558 + 3 + 8 + 87 = 666.

It is not a de Polignac number, because 645583887 - 2¹⁹ = 645059599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645583889) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 636793 + ... + 637805.

It is an arithmetic number, because the mean of its divisors is an integer number (28143570).

Almost surely, 2^645583887 is an apocalyptic number.

645583887 is a deficient number, since it is larger than the sum of its proper divisors (367584633).

645583887 is a wasteful number, since it uses less digits than its factorization.

645583887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1464 (or 1448 counting only the distinct ones).

The product of its digits is 6451200, while the sum is 54.

The square root of 645583887 is about 25408.3428621388. The cubic root of 645583887 is about 864.2728971738.

The spelling of 645583887 in words is "six hundred forty-five million, five hundred eighty-three thousand, eight hundred eighty-seven".