645779977546 has 16 divisors (see below), whose sum is σ = 1056746864448. Its totient is φ = 293531911200.

The previous prime is 645779977501. The next prime is 645779977547.

645779977546 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (645779977547) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1595011 + ... + 1958473.

It is an arithmetic number, because the mean of its divisors is an integer number (66046679028).

Almost surely, 2^645779977546 is an apocalyptic number.

645779977546 is a deficient number, since it is larger than the sum of its proper divisors (410966886902).

645779977546 is a wasteful number, since it uses less digits than its factorization.

645779977546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444237.

The product of its digits is 2800526400, while the sum is 76.

The spelling of 645779977546 in words is "six hundred forty-five billion, seven hundred seventy-nine million, nine hundred seventy-seven thousand, five hundred forty-six".