645501775 has 12 divisors (see below), whose sum is σ = 803259352. Its totient is φ = 514571040.

The previous prime is 645501737. The next prime is 645501793. The reversal of 645501775 is 577105546.

It is a happy number.

It is not a de Polignac number, because 645501775 - 2²¹ = 643404623 is a prime.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38544 + ... + 52693.

Almost surely, 2^645501775 is an apocalyptic number.

645501775 is a deficient number, since it is larger than the sum of its proper divisors (157757577).

645501775 is a wasteful number, since it uses less digits than its factorization.

645501775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91530 (or 91525 counting only the distinct ones).

The product of its (nonzero) digits is 147000, while the sum is 40.

The square root of 645501775 is about 25406.7269635425. The cubic root of 645501775 is about 864.2362532475.

The spelling of 645501775 in words is "six hundred forty-five million, five hundred one thousand, seven hundred seventy-five".