645684511 has 2 divisors, whose sum is σ = 645684512. Its totient is φ = 645684510.

The previous prime is 645684509. The next prime is 645684541. The reversal of 645684511 is 115486546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645684511 - 2¹ = 645684509 is a prime.

Together with 645684509, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645684541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322842255 + 322842256.

It is an arithmetic number, because the mean of its divisors is an integer number (322842256).

Almost surely, 2^645684511 is an apocalyptic number.

645684511 is a deficient number, since it is larger than the sum of its proper divisors (1).

645684511 is an equidigital number, since it uses as much as digits as its factorization.

645684511 is an evil number, because the sum of its binary digits is even.

The product of its digits is 115200, while the sum is 40.

The square root of 645684511 is about 25410.3229219937. The cubic root of 645684511 is about 864.3177981695.

The spelling of 645684511 in words is "six hundred forty-five million, six hundred eighty-four thousand, five hundred eleven".