21636708 has 12 divisors (see below), whose sum is σ = 50485680. Its totient is φ = 7212232.

The previous prime is 21636691. The next prime is 21636709. The reversal of 21636708 is 80763612.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21636709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 901518 + ... + 901541.

It is an arithmetic number, because the mean of its divisors is an integer number (4207140).

Almost surely, 2^21636708 is an apocalyptic number.

It is an amenable number.

21636708 is an abundant number, since it is smaller than the sum of its proper divisors (28848972).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21636708 is a wasteful number, since it uses less digits than its factorization.

21636708 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1803066 (or 1803064 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 21636708 is about 4651.5274910507. The cubic root of 21636708 is about 278.6530031787.

The spelling of 21636708 in words is "twenty-one million, six hundred thirty-six thousand, seven hundred eight".