21900523 has 2 divisors, whose sum is σ = 21900524. Its totient is φ = 21900522.

The previous prime is 21900509. The next prime is 21900533. The reversal of 21900523 is 32500912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21900523 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21900494 and 21900503.

It is not a weakly prime, because it can be changed into another prime (21900533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10950261 + 10950262.

It is an arithmetic number, because the mean of its divisors is an integer number (10950262).

Almost surely, 2^21900523 is an apocalyptic number.

21900523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21900523 is an equidigital number, since it uses as much as digits as its factorization.

21900523 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 21900523 is about 4679.7994615154. The cubic root of 21900523 is about 279.7809639030.

The spelling of 21900523 in words is "twenty-one million, nine hundred thousand, five hundred twenty-three".