21626457 has 8 divisors (see below), whose sum is σ = 28902720. Its totient is φ = 14383920.

The previous prime is 21626453. The next prime is 21626459. The reversal of 21626457 is 75462612.

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

It is not a de Polignac number, because 21626457 - 2² = 21626453 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21626453) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6894 + ... + 9527.

It is an arithmetic number, because the mean of its divisors is an integer number (3612840).

Almost surely, 2^21626457 is an apocalyptic number.

It is an amenable number.

21626457 is a deficient number, since it is larger than the sum of its proper divisors (7276263).

21626457 is a wasteful number, since it uses less digits than its factorization.

21626457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16863.

The product of its digits is 20160, while the sum is 33.

The square root of 21626457 is about 4650.4254644065. The cubic root of 21626457 is about 278.6089896568.

The spelling of 21626457 in words is "twenty-one million, six hundred twenty-six thousand, four hundred fifty-seven".