21626497 has 2 divisors, whose sum is σ = 21626498. Its totient is φ = 21626496.

The previous prime is 21626459. The next prime is 21626543. The reversal of 21626497 is 79462612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21538881 + 87616 = 4641^2 + 296^2 .

It is a cyclic number.

It is not a de Polignac number, because 21626497 - 2⁷ = 21626369 is a prime.

It is not a weakly prime, because it can be changed into another prime (21626447) 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 as a sum of consecutive naturals, namely, 10813248 + 10813249.

It is an arithmetic number, because the mean of its divisors is an integer number (10813249).

Almost surely, 2^21626497 is an apocalyptic number.

It is an amenable number.

21626497 is a deficient number, since it is larger than the sum of its proper divisors (1).

21626497 is an equidigital number, since it uses as much as digits as its factorization.

21626497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 37.

The square root of 21626497 is about 4650.4297650862. The cubic root of 21626497 is about 278.6091614271.

The spelling of 21626497 in words is "twenty-one million, six hundred twenty-six thousand, four hundred ninety-seven".