645451623605 has 16 divisors (see below), whose sum is σ = 820142812224. Its totient is φ = 485963654400.

The previous prime is 645451623499. The next prime is 645451623617. The reversal of 645451623605 is 506326154546.

It is not a de Polignac number, because 645451623605 - 2¹⁶ = 645451558069 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645451623605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1702154 + ... + 2046516.

It is an arithmetic number, because the mean of its divisors is an integer number (51258925764).

Almost surely, 2^645451623605 is an apocalyptic number.

It is an amenable number.

645451623605 is a deficient number, since it is larger than the sum of its proper divisors (174691188619).

645451623605 is a wasteful number, since it uses less digits than its factorization.

645451623605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366436.

The product of its (nonzero) digits is 2592000, while the sum is 47.

The spelling of 645451623605 in words is "six hundred forty-five billion, four hundred fifty-one million, six hundred twenty-three thousand, six hundred five".