21426015 has 32 divisors (see below), whose sum is σ = 38868480. Its totient is φ = 9991296.

The previous prime is 21425993. The next prime is 21426017. The reversal of 21426015 is 51062412.

It is not a de Polignac number, because 21426015 - 2⁸ = 21425759 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21425982 and 21426000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21426017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 814 + ... + 6596.

It is an arithmetic number, because the mean of its divisors is an integer number (1214640).

Almost surely, 2^21426015 is an apocalyptic number.

21426015 is a deficient number, since it is larger than the sum of its proper divisors (17442465).

21426015 is a wasteful number, since it uses less digits than its factorization.

21426015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5823.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21426015 is about 4628.8243647821. The cubic root of 21426015 is about 277.7455662500.

Adding to 21426015 its reverse (51062412), we get a palindrome (72488427).

The spelling of 21426015 in words is "twenty-one million, four hundred twenty-six thousand, fifteen".