645720614 has 24 divisors (see below), whose sum is σ = 1216732944. Its totient is φ = 251578800.

The previous prime is 645720613. The next prime is 645720617. The reversal of 645720614 is 416027546.

It is a super-2 number, since 2×645720614² = 833910222689073992, which contains 22 as substring.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645720613) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 188897 + ... + 192284.

It is an arithmetic number, because the mean of its divisors is an integer number (50697206).

Almost surely, 2^645720614 is an apocalyptic number.

645720614 is a deficient number, since it is larger than the sum of its proper divisors (571012330).

645720614 is a wasteful number, since it uses less digits than its factorization.

645720614 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381212 (or 381201 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 645720614 is about 25411.0333123232. The cubic root of 645720614 is about 864.3339071120. Note that the first 3 decimals are identical.

The spelling of 645720614 in words is "six hundred forty-five million, seven hundred twenty thousand, six hundred fourteen".