645750553 has 32 divisors (see below), whose sum is σ = 802897920. Its totient is φ = 507228480.

The previous prime is 645750551. The next prime is 645750557. The reversal of 645750553 is 355057546.

It is a cyclic number.

It is not a de Polignac number, because 645750553 - 2¹ = 645750551 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645750551) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 543426 + ... + 544612.

It is an arithmetic number, because the mean of its divisors is an integer number (25090560).

Almost surely, 2^645750553 is an apocalyptic number.

It is an amenable number.

645750553 is a deficient number, since it is larger than the sum of its proper divisors (157147367).

645750553 is a wasteful number, since it uses less digits than its factorization.

645750553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1357.

The product of its (nonzero) digits is 315000, while the sum is 40.

The square root of 645750553 is about 25411.6223999964. The cubic root of 645750553 is about 864.3472652591.

The spelling of 645750553 in words is "six hundred forty-five million, seven hundred fifty thousand, five hundred fifty-three".