21550519 has 2 divisors, whose sum is σ = 21550520. Its totient is φ = 21550518.

The previous prime is 21550513. The next prime is 21550537. The reversal of 21550519 is 91505512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21550519 - 2⁹ = 21550007 is a prime.

It is a super-2 number, since 2×21550519² = 928849738338722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21550513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10775259 + 10775260.

It is an arithmetic number, because the mean of its divisors is an integer number (10775260).

Almost surely, 2^21550519 is an apocalyptic number.

21550519 is a deficient number, since it is larger than the sum of its proper divisors (1).

21550519 is an equidigital number, since it uses as much as digits as its factorization.

21550519 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2250, while the sum is 28.

The square root of 21550519 is about 4642.2536552843. The cubic root of 21550519 is about 278.2825095946.

The spelling of 21550519 in words is "twenty-one million, five hundred fifty thousand, five hundred nineteen".