21422515 has 4 divisors (see below), whose sum is σ = 25707024. Its totient is φ = 17138008.

The previous prime is 21422501. The next prime is 21422537. The reversal of 21422515 is 51522412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21422515 - 2⁵ = 21422483 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2142247 + ... + 2142256.

It is an arithmetic number, because the mean of its divisors is an integer number (6426756).

Almost surely, 2^21422515 is an apocalyptic number.

21422515 is a deficient number, since it is larger than the sum of its proper divisors (4284509).

21422515 is an equidigital number, since it uses as much as digits as its factorization.

21422515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4284508.

The product of its digits is 800, while the sum is 22.

The square root of 21422515 is about 4628.4462835816. The cubic root of 21422515 is about 277.7304419192.

Adding to 21422515 its reverse (51522412), we get a palindrome (72944927).

The spelling of 21422515 in words is "twenty-one million, four hundred twenty-two thousand, five hundred fifteen".