645411621 has 8 divisors (see below), whose sum is σ = 864340704. Its totient is φ = 428378480.

The previous prime is 645411601. The next prime is 645411623. The reversal of 645411621 is 126114546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645411621 - 2²⁵ = 611857189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645411623) 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, 473190 + ... + 474551.

It is an arithmetic number, because the mean of its divisors is an integer number (108042588).

Almost surely, 2^645411621 is an apocalyptic number.

It is an amenable number.

645411621 is a deficient number, since it is larger than the sum of its proper divisors (218929083).

645411621 is a wasteful number, since it uses less digits than its factorization.

645411621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 947971.

The product of its digits is 5760, while the sum is 30.

The square root of 645411621 is about 25404.9526864350. The cubic root of 645411621 is about 864.1960168579.

The spelling of 645411621 in words is "six hundred forty-five million, four hundred eleven thousand, six hundred twenty-one".