21905519 has 2 divisors, whose sum is σ = 21905520. Its totient is φ = 21905518.

The previous prime is 21905501. The next prime is 21905531. The reversal of 21905519 is 91550912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21905519 - 2⁸ = 21905263 is a prime.

It is a super-2 number, since 2×21905519² = 959703525318722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21901519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10952759 + 10952760.

It is an arithmetic number, because the mean of its divisors is an integer number (10952760).

Almost surely, 2^21905519 is an apocalyptic number.

21905519 is a deficient number, since it is larger than the sum of its proper divisors (1).

21905519 is an equidigital number, since it uses as much as digits as its factorization.

21905519 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4050, while the sum is 32.

The square root of 21905519 is about 4680.3332146333. Note that the first 3 decimals coincide. The cubic root of 21905519 is about 279.8022370543.

The spelling of 21905519 in words is "twenty-one million, nine hundred five thousand, five hundred nineteen".