645015871 has 2 divisors, whose sum is σ = 645015872. Its totient is φ = 645015870.

The previous prime is 645015869. The next prime is 645015911. The reversal of 645015871 is 178510546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645015871 - 2¹ = 645015869 is a prime.

Together with 645015869, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 645015871.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645015821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322507935 + 322507936.

It is an arithmetic number, because the mean of its divisors is an integer number (322507936).

Almost surely, 2^645015871 is an apocalyptic number.

645015871 is a deficient number, since it is larger than the sum of its proper divisors (1).

645015871 is an equidigital number, since it uses as much as digits as its factorization.

645015871 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 33600, while the sum is 37.

The square root of 645015871 is about 25397.1626564859. The cubic root of 645015871 is about 864.0193463996.

The spelling of 645015871 in words is "six hundred forty-five million, fifteen thousand, eight hundred seventy-one".