21456321858 has 24 divisors (see below), whose sum is σ = 46506297708. Its totient is φ = 7149399552.

The previous prime is 21456321853. The next prime is 21456321863. The reversal of 21456321858 is 85812365412.

21456321858 is a `hidden beast` number, since 2 + 1 + 4 + 5 + 632 + 1 + 8 + 5 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (21456321853) and next prime (21456321863).

It can be written as a sum of positive squares in 2 ways, for example, as 21153666249 + 302655609 = 145443^2 + 17397^2 .

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21456321851) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 176491 + ... + 272142.

Almost surely, 2^21456321858 is an apocalyptic number.

21456321858 is an abundant number, since it is smaller than the sum of its proper divisors (25049975850).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21456321858 is a wasteful number, since it uses less digits than its factorization.

21456321858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451298 (or 451295 counting only the distinct ones).

The product of its digits is 460800, while the sum is 45.

The spelling of 21456321858 in words is "twenty-one billion, four hundred fifty-six million, three hundred twenty-one thousand, eight hundred fifty-eight".