21626361 has 12 divisors (see below), whose sum is σ = 31375188. Its totient is φ = 14354304.

The previous prime is 21626359. The next prime is 21626369. The reversal of 21626361 is 16362612.

21626361 is a `hidden beast` number, since 2 + 1 + 626 + 36 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 6533136 + 15093225 = 2556^2 + 3885^2 .

It is not a de Polignac number, because 21626361 - 2¹ = 21626359 is a prime.

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

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3060 + ... + 7253.

It is an arithmetic number, because the mean of its divisors is an integer number (2614599).

Almost surely, 2^21626361 is an apocalyptic number.

It is an amenable number.

21626361 is a deficient number, since it is larger than the sum of its proper divisors (9748827).

21626361 is a wasteful number, since it uses less digits than its factorization.

21626361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10552 (or 10549 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 21626361 is about 4650.4151427588. The cubic root of 21626361 is about 278.6085774070.

Adding to 21626361 its reverse (16362612), we get a palindrome (37988973).

The spelling of 21626361 in words is "twenty-one million, six hundred twenty-six thousand, three hundred sixty-one".