21364897 has 2 divisors, whose sum is σ = 21364898. Its totient is φ = 21364896.

The previous prime is 21364877. The next prime is 21364919. The reversal of 21364897 is 79846312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19927296 + 1437601 = 4464^2 + 1199^2 .

It is a cyclic number.

It is not a de Polignac number, because 21364897 - 2¹⁹ = 20840609 is a prime.

It is not a weakly prime, because it can be changed into another prime (21364807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10682448 + 10682449.

It is an arithmetic number, because the mean of its divisors is an integer number (10682449).

Almost surely, 2^21364897 is an apocalyptic number.

It is an amenable number.

21364897 is a deficient number, since it is larger than the sum of its proper divisors (1).

21364897 is an equidigital number, since it uses as much as digits as its factorization.

21364897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 40.

The square root of 21364897 is about 4622.2177577436. The cubic root of 21364897 is about 277.4812237384.

The spelling of 21364897 in words is "twenty-one million, three hundred sixty-four thousand, eight hundred ninety-seven".