645104391 has 48 divisors (see below), whose sum is σ = 946028160. Its totient is φ = 390470080.

The previous prime is 645104381. The next prime is 645104419. The reversal of 645104391 is 193401546.

It is not a de Polignac number, because 645104391 - 2²² = 640910087 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645104311) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4924396 + ... + 4924526.

It is an arithmetic number, because the mean of its divisors is an integer number (19708920).

Almost surely, 2^645104391 is an apocalyptic number.

645104391 is a deficient number, since it is larger than the sum of its proper divisors (300923769).

645104391 is a wasteful number, since it uses less digits than its factorization.

645104391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316 (or 293 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 645104391 is about 25398.9053110562. The cubic root of 645104391 is about 864.0588697135.

The spelling of 645104391 in words is "six hundred forty-five million, one hundred four thousand, three hundred ninety-one".