645881334 has 32 divisors (see below), whose sum is σ = 1478822400. Its totient is φ = 184222272.

The previous prime is 645881333. The next prime is 645881381. The reversal of 645881334 is 433188546.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645881333) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12322 + ... + 37994.

It is an arithmetic number, because the mean of its divisors is an integer number (46213200).

Almost surely, 2^645881334 is an apocalyptic number.

645881334 is an abundant number, since it is smaller than the sum of its proper divisors (832941066).

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

645881334 is a wasteful number, since it uses less digits than its factorization.

645881334 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26284.

The product of its digits is 276480, while the sum is 42.

The square root of 645881334 is about 25414.1955214010. The cubic root of 645881334 is about 864.4056121285.

The spelling of 645881334 in words is "six hundred forty-five million, eight hundred eighty-one thousand, three hundred thirty-four".