21654036 has 36 divisors (see below), whose sum is σ = 55403712. Its totient is φ = 7130064.

The previous prime is 21654029. The next prime is 21654037. The reversal of 21654036 is 63045612.

21654036 is a `hidden beast` number, since 2 + 1 + 654 + 0 + 3 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21654037) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 636 + ... + 6611.

It is an arithmetic number, because the mean of its divisors is an integer number (1538992).

Almost surely, 2^21654036 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21654036, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27701856).

21654036 is an abundant number, since it is smaller than the sum of its proper divisors (33749676).

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

21654036 is a wasteful number, since it uses less digits than its factorization.

21654036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7340 (or 7335 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 21654036 is about 4653.3897322275. The cubic root of 21654036 is about 278.7273707893.

Adding to 21654036 its reverse (63045612), we get a palindrome (84699648).

The spelling of 21654036 in words is "twenty-one million, six hundred fifty-four thousand, thirty-six".