645398975 has 24 divisors (see below), whose sum is σ = 899338272. Its totient is φ = 455875200.

The previous prime is 645398969. The next prime is 645398981. The reversal of 645398975 is 579893546.

It is a happy number.

645398975 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (645398969) and next prime (645398981).

It is not a de Polignac number, because 645398975 - 2¹² = 645394879 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645398975.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35696 + ... + 50645.

It is an arithmetic number, because the mean of its divisors is an integer number (37472428).

Almost surely, 2^645398975 is an apocalyptic number.

645398975 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

645398975 is a deficient number, since it is larger than the sum of its proper divisors (253939297).

645398975 is a wasteful number, since it uses less digits than its factorization.

645398975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86387 (or 86382 counting only the distinct ones).

The product of its digits is 8164800, while the sum is 56.

The square root of 645398975 is about 25404.7037967381. The cubic root of 645398975 is about 864.1903725560.

The spelling of 645398975 in words is "six hundred forty-five million, three hundred ninety-eight thousand, nine hundred seventy-five".