645739231 has 2 divisors, whose sum is σ = 645739232. Its totient is φ = 645739230.

The previous prime is 645739219. The next prime is 645739261. The reversal of 645739231 is 132937546.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645739231 - 2¹³ = 645731039 is a prime.

It is a super-2 number, since 2×645739231² = 833958308904942722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645739261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322869615 + 322869616.

It is an arithmetic number, because the mean of its divisors is an integer number (322869616).

Almost surely, 2^645739231 is an apocalyptic number.

645739231 is a deficient number, since it is larger than the sum of its proper divisors (1).

645739231 is an equidigital number, since it uses as much as digits as its factorization.

645739231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 40.

The square root of 645739231 is about 25411.3996269391. The cubic root of 645739231 is about 864.3422136713.

The spelling of 645739231 in words is "six hundred forty-five million, seven hundred thirty-nine thousand, two hundred thirty-one".