645387971 has 2 divisors, whose sum is σ = 645387972. Its totient is φ = 645387970.

The previous prime is 645387937. The next prime is 645388031. The reversal of 645387971 is 179783546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645387971 - 2²² = 641193667 is a prime.

It is a super-2 number, since 2×645387971² = 833051266222993682, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (645387931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322693985 + 322693986.

It is an arithmetic number, because the mean of its divisors is an integer number (322693986).

Almost surely, 2^645387971 is an apocalyptic number.

645387971 is a deficient number, since it is larger than the sum of its proper divisors (1).

645387971 is an equidigital number, since it uses as much as digits as its factorization.

645387971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1270080, while the sum is 50.

The square root of 645387971 is about 25404.4872217488. The cubic root of 645387971 is about 864.1854610695.

The spelling of 645387971 in words is "six hundred forty-five million, three hundred eighty-seven thousand, nine hundred seventy-one".