645731039 has 2 divisors, whose sum is σ = 645731040. Its totient is φ = 645731038.

The previous prime is 645731029. The next prime is 645731041. The reversal of 645731039 is 930137546.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645731039 - 2²⁰ = 644682463 is a prime.

Together with 645731041, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 645730993 and 645731011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645731029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322865519 + 322865520.

It is an arithmetic number, because the mean of its divisors is an integer number (322865520).

Almost surely, 2^645731039 is an apocalyptic number.

645731039 is a deficient number, since it is larger than the sum of its proper divisors (1).

645731039 is an equidigital number, since it uses as much as digits as its factorization.

645731039 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 68040, while the sum is 38.

The square root of 645731039 is about 25411.2384389270. The cubic root of 645731039 is about 864.3385585729.

The spelling of 645731039 in words is "six hundred forty-five million, seven hundred thirty-one thousand, thirty-nine".