645128371 has 2 divisors, whose sum is σ = 645128372. Its totient is φ = 645128370.

The previous prime is 645128293. The next prime is 645128401. The reversal of 645128371 is 173821546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645128371 - 2²⁵ = 611573939 is a prime.

It is a super-2 number, since 2×645128371² = 832381230138227282, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 645128371.

It is not a weakly prime, because it can be changed into another prime (645228371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322564185 + 322564186.

It is an arithmetic number, because the mean of its divisors is an integer number (322564186).

Almost surely, 2^645128371 is an apocalyptic number.

645128371 is a deficient number, since it is larger than the sum of its proper divisors (1).

645128371 is an equidigital number, since it uses as much as digits as its factorization.

645128371 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 37.

The square root of 645128371 is about 25399.3773742586. The cubic root of 645128371 is about 864.0695759264.

The spelling of 645128371 in words is "six hundred forty-five million, one hundred twenty-eight thousand, three hundred seventy-one".