21881626 has 8 divisors (see below), whose sum is σ = 35347284. Its totient is φ = 10099200.

The previous prime is 21881621. The next prime is 21881627. The reversal of 21881626 is 62618812.

It can be written as a sum of positive squares in 2 ways, for example, as 19793601 + 2088025 = 4449^2 + 1445^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21881591 and 21881600.

It is not an unprimeable number, because it can be changed into a prime (21881621) 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 3 ways as a sum of consecutive naturals, for example, 420775 + ... + 420826.

Almost surely, 2^21881626 is an apocalyptic number.

21881626 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21881626 is a deficient number, since it is larger than the sum of its proper divisors (13465658).

21881626 is a wasteful number, since it uses less digits than its factorization.

21881626 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 841616.

The product of its digits is 9216, while the sum is 34.

The square root of 21881626 is about 4677.7800290309. The cubic root of 21881626 is about 279.7004705095.

The spelling of 21881626 in words is "twenty-one million, eight hundred eighty-one thousand, six hundred twenty-six".