645296661 has 24 divisors (see below), whose sum is σ = 968647680. Its totient is φ = 413463456.

The previous prime is 645296647. The next prime is 645296683. The reversal of 645296661 is 166692546.

645296661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-645296661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645296621) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 52660 + ... + 63746.

It is an arithmetic number, because the mean of its divisors is an integer number (40360320).

Almost surely, 2^645296661 is an apocalyptic number.

It is an amenable number.

645296661 is a deficient number, since it is larger than the sum of its proper divisors (323351019).

645296661 is a wasteful number, since it uses less digits than its factorization.

645296661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11345 (or 11342 counting only the distinct ones).

The product of its digits is 466560, while the sum is 45.

The square root of 645296661 is about 25402.6900347188. The cubic root of 645296661 is about 864.1447039334.

The spelling of 645296661 in words is "six hundred forty-five million, two hundred ninety-six thousand, six hundred sixty-one".