21940608 has 64 divisors (see below), whose sum is σ = 61726320. Its totient is φ = 6881280.

The previous prime is 21940603. The next prime is 21940637. The reversal of 21940608 is 80604912.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21940601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4848 + ... + 8208.

Almost surely, 2^21940608 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 21940608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30863160).

21940608 is an abundant number, since it is smaller than the sum of its proper divisors (39785712).

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

21940608 is a wasteful number, since it uses less digits than its factorization.

21940608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3395 (or 3383 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 21940608 is about 4684.0802725829. The cubic root of 21940608 is about 279.9515562449.

The spelling of 21940608 in words is "twenty-one million, nine hundred forty thousand, six hundred eight".