21528497 has 2 divisors, whose sum is σ = 21528498. Its totient is φ = 21528496.

The previous prime is 21528467. The next prime is 21528517. The reversal of 21528497 is 79482512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18054001 + 3474496 = 4249^2 + 1864^2 .

It is a cyclic number.

It is not a de Polignac number, because 21528497 - 2⁶ = 21528433 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21528497.

It is not a weakly prime, because it can be changed into another prime (21528467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10764248 + 10764249.

It is an arithmetic number, because the mean of its divisors is an integer number (10764249).

Almost surely, 2^21528497 is an apocalyptic number.

It is an amenable number.

21528497 is a deficient number, since it is larger than the sum of its proper divisors (1).

21528497 is an equidigital number, since it uses as much as digits as its factorization.

21528497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 38.

The square root of 21528497 is about 4639.8811407190. The cubic root of 21528497 is about 278.1876870355.

The spelling of 21528497 in words is "twenty-one million, five hundred twenty-eight thousand, four hundred ninety-seven".