645606624021 has 16 divisors (see below), whose sum is σ = 877083842304. Its totient is φ = 422267528384.

The previous prime is 645606624017. The next prime is 645606624043. The reversal of 645606624021 is 120426606546.

It is a cyclic number.

It is not a de Polignac number, because 645606624021 - 2² = 645606624017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645606624011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5289535 + ... + 5410211.

It is an arithmetic number, because the mean of its divisors is an integer number (54817740144).

Almost surely, 2^645606624021 is an apocalyptic number.

It is an amenable number.

645606624021 is a deficient number, since it is larger than the sum of its proper divisors (231477218283).

645606624021 is a wasteful number, since it uses less digits than its factorization.

645606624021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154380.

The product of its (nonzero) digits is 414720, while the sum is 42.

The spelling of 645606624021 in words is "six hundred forty-five billion, six hundred six million, six hundred twenty-four thousand, twenty-one".