21806023420 has 24 divisors (see below), whose sum is σ = 48486335184. Its totient is φ = 8209326336.

The previous prime is 21806023409. The next prime is 21806023487. The reversal of 21806023420 is 2432060812.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32067342 + ... + 32068021.

It is an arithmetic number, because the mean of its divisors is an integer number (2020263966).

Almost surely, 2^21806023420 is an apocalyptic number.

21806023420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21806023420 is an abundant number, since it is smaller than the sum of its proper divisors (26680311764).

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

21806023420 is a wasteful number, since it uses less digits than its factorization.

21806023420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64135389 (or 64135387 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The spelling of 21806023420 in words is "twenty-one billion, eight hundred six million, twenty-three thousand, four hundred twenty".