645272651766 has 32 divisors (see below), whose sum is σ = 1363373026560. Its totient is φ = 203034668256.

The previous prime is 645272651759. The next prime is 645272651783. The reversal of 645272651766 is 667156272546.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent 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, 10185546 + ... + 10248701.

It is an arithmetic number, because the mean of its divisors is an integer number (42605407080).

Almost surely, 2^645272651766 is an apocalyptic number.

645272651766 is an abundant number, since it is smaller than the sum of its proper divisors (718100374794).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645272651766 is a wasteful number, since it uses less digits than its factorization.

645272651766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20434548.

The product of its digits is 25401600, while the sum is 57.

The spelling of 645272651766 in words is "six hundred forty-five billion, two hundred seventy-two million, six hundred fifty-one thousand, seven hundred sixty-six".