1645731894 has 16 divisors (see below), whose sum is σ = 3311175168. Its totient is φ = 545292072.

The previous prime is 1645731877. The next prime is 1645731959. The reversal of 1645731894 is 4981375461.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 820222 + ... + 822225.

It is an arithmetic number, because the mean of its divisors is an integer number (206948448).

Almost surely, 2^1645731894 is an apocalyptic number.

1645731894 is an abundant number, since it is smaller than the sum of its proper divisors (1665443274).

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

1645731894 is a wasteful number, since it uses less digits than its factorization.

1645731894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1642619.

The product of its digits is 725760, while the sum is 48.

The square root of 1645731894 is about 40567.6212514365. The cubic root of 1645731894 is about 1180.6459869031.

The spelling of 1645731894 in words is "one billion, six hundred forty-five million, seven hundred thirty-one thousand, eight hundred ninety-four".