645739239 has 16 divisors (see below), whose sum is σ = 881284352. Its totient is φ = 420458688.

The previous prime is 645739231. The next prime is 645739261. The reversal of 645739239 is 932937546.

It is a happy number.

It is not a de Polignac number, because 645739239 - 2³ = 645739231 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645739231) 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, 8244 + ... + 36870.

It is an arithmetic number, because the mean of its divisors is an integer number (55080272).

Almost surely, 2^645739239 is an apocalyptic number.

645739239 is a deficient number, since it is larger than the sum of its proper divisors (235545113).

645739239 is a wasteful number, since it uses less digits than its factorization.

645739239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28806.

The product of its digits is 1224720, while the sum is 48.

The square root of 645739239 is about 25411.3997843488. The cubic root of 645739239 is about 864.3422172407.

The spelling of 645739239 in words is "six hundred forty-five million, seven hundred thirty-nine thousand, two hundred thirty-nine".