21523606 has 32 divisors (see below), whose sum is σ = 36310176. Its totient is φ = 9504000.

The previous prime is 21523591. The next prime is 21523609. The reversal of 21523606 is 60632512.

It is a Smith number, since the sum of its digits (25) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64861 + ... + 65191.

It is an arithmetic number, because the mean of its divisors is an integer number (1134693).

Almost surely, 2^21523606 is an apocalyptic number.

21523606 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21523606 is a deficient number, since it is larger than the sum of its proper divisors (14786570).

21523606 is a wasteful number, since it uses less digits than its factorization.

21523606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 21523606 is about 4639.3540498651. The cubic root of 21523606 is about 278.1666185415.

The spelling of 21523606 in words is "twenty-one million, five hundred twenty-three thousand, six hundred six".