645302017621 has 8 divisors (see below), whose sum is σ = 683512855704. Its totient is φ = 607119168000.

The previous prime is 645302017583. The next prime is 645302017667. The reversal of 645302017621 is 126710203546.

It can be written as a sum of positive squares in 4 ways, for example, as 300364283025 + 344937734596 = 548055^2 + 587314^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645302017621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645302017721) 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, 6949630 + ... + 7041871.

It is an arithmetic number, because the mean of its divisors is an integer number (85439106963).

Almost surely, 2^645302017621 is an apocalyptic number.

It is an amenable number.

645302017621 is a deficient number, since it is larger than the sum of its proper divisors (38210838083).

645302017621 is a wasteful number, since it uses less digits than its factorization.

645302017621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13994231.

The product of its (nonzero) digits is 60480, while the sum is 37.

The spelling of 645302017621 in words is "six hundred forty-five billion, three hundred two million, seventeen thousand, six hundred twenty-one".