21621426 has 16 divisors (see below), whose sum is σ = 45123264. Its totient is φ = 6893744.

The previous prime is 21621421. The next prime is 21621427. The reversal of 21621426 is 62412612.

It is a junction number, because it is equal to n+sod(n) for n = 21621396 and 21621405.

It is not an unprimeable number, because it can be changed into a prime (21621421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78201 + ... + 78476.

It is an arithmetic number, because the mean of its divisors is an integer number (2820204).

Almost surely, 2^21621426 is an apocalyptic number.

21621426 is an abundant number, since it is smaller than the sum of its proper divisors (23501838).

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

21621426 is a wasteful number, since it uses less digits than its factorization.

21621426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156705.

The product of its digits is 1152, while the sum is 24.

The square root of 21621426 is about 4649.8845146950. The cubic root of 21621426 is about 278.5873835513.

The spelling of 21621426 in words is "twenty-one million, six hundred twenty-one thousand, four hundred twenty-six".