21642526 has 16 divisors (see below), whose sum is σ = 34669440. Its totient is φ = 10110240.

The previous prime is 21642503. The next prime is 21642527. The reversal of 21642526 is 62524612.

It is a junction number, because it is equal to n+sod(n) for n = 21642494 and 21642503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21642527) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 4221 + ... + 7816.

It is an arithmetic number, because the mean of its divisors is an integer number (2166840).

Almost surely, 2^21642526 is an apocalyptic number.

21642526 is a deficient number, since it is larger than the sum of its proper divisors (13026914).

21642526 is a wasteful number, since it uses less digits than its factorization.

21642526 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12099.

The product of its digits is 5760, while the sum is 28.

The square root of 21642526 is about 4652.1528349787. The cubic root of 21642526 is about 278.6779770623.

The spelling of 21642526 in words is "twenty-one million, six hundred forty-two thousand, five hundred twenty-six".