645238799 has 2 divisors, whose sum is σ = 645238800. Its totient is φ = 645238798.

The previous prime is 645238787. The next prime is 645238807. The reversal of 645238799 is 997832546.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645238799 - 2⁸ = 645238543 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645238799.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645238739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322619399 + 322619400.

It is an arithmetic number, because the mean of its divisors is an integer number (322619400).

Almost surely, 2^645238799 is an apocalyptic number.

645238799 is a deficient number, since it is larger than the sum of its proper divisors (1).

645238799 is an equidigital number, since it uses as much as digits as its factorization.

645238799 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3265920, while the sum is 53.

The square root of 645238799 is about 25401.5511140560. The cubic root of 645238799 is about 864.1188746581.

The spelling of 645238799 in words is "six hundred forty-five million, two hundred thirty-eight thousand, seven hundred ninety-nine".