645943634 has 16 divisors (see below), whose sum is σ = 1107711936. Its totient is φ = 276738000.

The previous prime is 645943631. The next prime is 645943637. The reversal of 645943634 is 436349546.

It is an interprime number because it is at equal distance from previous prime (645943631) and next prime (645943637).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (645943631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47924 + ... + 59904.

It is an arithmetic number, because the mean of its divisors is an integer number (69231996).

Almost surely, 2^645943634 is an apocalyptic number.

645943634 is a deficient number, since it is larger than the sum of its proper divisors (461768302).

645943634 is a wasteful number, since it uses less digits than its factorization.

645943634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15841.

The product of its digits is 933120, while the sum is 44.

The square root of 645943634 is about 25415.4211847846. The cubic root of 645943634 is about 864.4334039923.

The spelling of 645943634 in words is "six hundred forty-five million, nine hundred forty-three thousand, six hundred thirty-four".