645301850661 has 64 divisors (see below), whose sum is σ = 1063492864000. Its totient is φ = 384031134720.

The previous prime is 645301850653. The next prime is 645301850779. The reversal of 645301850661 is 166058103546.

645301850661 is a `hidden beast` number, since 6 + 4 + 530 + 1 + 8 + 50 + 6 + 61 = 666.

It is not a de Polignac number, because 645301850661 - 2³ = 645301850653 is a prime.

It is a super-2 number, since 2×645301850661² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645301850621) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16181895 + ... + 16221723.

It is an arithmetic number, because the mean of its divisors is an integer number (16617076000).

Almost surely, 2^645301850661 is an apocalyptic number.

It is an amenable number.

645301850661 is a deficient number, since it is larger than the sum of its proper divisors (418191013339).

645301850661 is a wasteful number, since it uses less digits than its factorization.

645301850661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41371 (or 41365 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

It can be divided in two parts, 64530 and 1850661, that added together give a palindrome (1915191).

The spelling of 645301850661 in words is "six hundred forty-five billion, three hundred one million, eight hundred fifty thousand, six hundred sixty-one".