21654936 has 48 divisors (see below), whose sum is σ = 59537400. Its totient is φ = 7110576.

The previous prime is 21654931. The next prime is 21654943. The reversal of 21654936 is 63945612.

It is a happy number.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

21654936 is a `hidden beast` number, since 2 + 165 + 493 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

Its product of digits (38880) is a multiple of the sum of its prime divisors (72).

It is a self number, because there is not a number n which added to its sum of digits gives 21654936.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21654931) 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, 323175 + ... + 323241.

Almost surely, 2^21654936 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 21654936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29768700).

21654936 is an abundant number, since it is smaller than the sum of its proper divisors (37882464).

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

21654936 is an frugal number, since it uses more digits than its factorization.

21654936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213 (or 72 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 21654936 is about 4653.4864349217. The cubic root of 21654936 is about 278.7312322890.

The spelling of 21654936 in words is "twenty-one million, six hundred fifty-four thousand, nine hundred thirty-six".