645442079 has 2 divisors, whose sum is σ = 645442080. Its totient is φ = 645442078.

The previous prime is 645442051. The next prime is 645442099. The reversal of 645442079 is 970244546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645442079 - 2²⁴ = 628664863 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645442099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322721039 + 322721040.

It is an arithmetic number, because the mean of its divisors is an integer number (322721040).

Almost surely, 2^645442079 is an apocalyptic number.

645442079 is a deficient number, since it is larger than the sum of its proper divisors (1).

645442079 is an equidigital number, since it uses as much as digits as its factorization.

645442079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 241920, while the sum is 41.

The square root of 645442079 is about 25405.5521294067. The cubic root of 645442079 is about 864.2096109052.

The spelling of 645442079 in words is "six hundred forty-five million, four hundred forty-two thousand, seventy-nine".