21626365 has 4 divisors (see below), whose sum is σ = 25951644. Its totient is φ = 17301088.

The previous prime is 21626359. The next prime is 21626369. The reversal of 21626365 is 56362612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13111641 + 8514724 = 3621^2 + 2918^2 .

It is a cyclic number.

It is not a de Polignac number, because 21626365 - 2¹⁵ = 21593597 is a prime.

It is a super-2 number, since 2×21626365² = 935399326226450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21626369) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2162632 + ... + 2162641.

It is an arithmetic number, because the mean of its divisors is an integer number (6487911).

Almost surely, 2^21626365 is an apocalyptic number.

It is an amenable number.

21626365 is a deficient number, since it is larger than the sum of its proper divisors (4325279).

21626365 is an equidigital number, since it uses as much as digits as its factorization.

21626365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4325278.

The product of its digits is 12960, while the sum is 31.

The square root of 21626365 is about 4650.4155728279. The cubic root of 21626365 is about 278.6085945841.

Adding to 21626365 its reverse (56362612), we get a palindrome (77988977).

The spelling of 21626365 in words is "twenty-one million, six hundred twenty-six thousand, three hundred sixty-five".