21682519 has 2 divisors, whose sum is σ = 21682520. Its totient is φ = 21682518.

The previous prime is 21682501. The next prime is 21682589. The reversal of 21682519 is 91528612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21682519 - 2⁵ = 21682487 is a prime.

It is a super-2 number, since 2×21682519² = 940263260370722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21682589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10841259 + 10841260.

It is an arithmetic number, because the mean of its divisors is an integer number (10841260).

Almost surely, 2^21682519 is an apocalyptic number.

21682519 is a deficient number, since it is larger than the sum of its proper divisors (1).

21682519 is an equidigital number, since it uses as much as digits as its factorization.

21682519 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 34.

The square root of 21682519 is about 4656.4491836592. The cubic root of 21682519 is about 278.8495268214.

It can be divided in two parts, 21682 and 519, that added together give a square (22201 = 149²).

The spelling of 21682519 in words is "twenty-one million, six hundred eighty-two thousand, five hundred nineteen".