645442641 has 8 divisors (see below), whose sum is σ = 956211360. Its totient is φ = 430295076.

The previous prime is 645442631. The next prime is 645442643. The reversal of 645442641 is 146244546.

645442641 is a `hidden beast` number, since 6 + 4 + 5 + 4 + 4 + 2 + 641 = 666.

It is not a de Polignac number, because 645442641 - 2²⁵ = 611888209 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 645442596 and 645442605.

It is not an unprimeable number, because it can be changed into a prime (645442643) 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, 11952615 + ... + 11952668.

It is an arithmetic number, because the mean of its divisors is an integer number (119526420).

Almost surely, 2^645442641 is an apocalyptic number.

It is an amenable number.

645442641 is a deficient number, since it is larger than the sum of its proper divisors (310768719).

645442641 is a wasteful number, since it uses less digits than its factorization.

645442641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23905292 (or 23905286 counting only the distinct ones).

The product of its digits is 92160, while the sum is 36.

The square root of 645442641 is about 25405.5631899787. The cubic root of 645442641 is about 864.2098617336.

The spelling of 645442641 in words is "six hundred forty-five million, four hundred forty-two thousand, six hundred forty-one".