21523634 has 8 divisors (see below), whose sum is σ = 35220528. Its totient is φ = 9783460.

The previous prime is 21523631. The next prime is 21523651. The reversal of 21523634 is 43632512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a plaindrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (21523631) 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 3 ways as a sum of consecutive naturals, for example, 489152 + ... + 489195.

It is an arithmetic number, because the mean of its divisors is an integer number (4402566).

Almost surely, 2^21523634 is an apocalyptic number.

21523634 is a deficient number, since it is larger than the sum of its proper divisors (13696894).

21523634 is a wasteful number, since it uses less digits than its factorization.

21523634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 978360.

The product of its digits is 4320, while the sum is 26.

The square root of 21523634 is about 4639.3570675256. The cubic root of 21523634 is about 278.1667391635.

The spelling of 21523634 in words is "twenty-one million, five hundred twenty-three thousand, six hundred thirty-four".