645621236421 has 32 divisors (see below), whose sum is σ = 1000149037056. Its totient is φ = 362822880000.

The previous prime is 645621236399. The next prime is 645621236423. The reversal of 645621236421 is 124632126546.

It is a happy number.

It is not a de Polignac number, because 645621236421 - 2²³ = 645612847813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645621236423) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 57976 + ... + 1137806.

It is an arithmetic number, because the mean of its divisors is an integer number (31254657408).

Almost surely, 2^645621236421 is an apocalyptic number.

It is an amenable number.

645621236421 is a deficient number, since it is larger than the sum of its proper divisors (354527800635).

645621236421 is a wasteful number, since it uses less digits than its factorization.

645621236421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1080313.

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

The spelling of 645621236421 in words is "six hundred forty-five billion, six hundred twenty-one million, two hundred thirty-six thousand, four hundred twenty-one".