21940308 has 60 divisors (see below), whose sum is σ = 61780180. Its totient is φ = 6749568.

The previous prime is 21940291. The next prime is 21940309. The reversal of 21940308 is 80304912.

It can be written as a sum of positive squares in 2 ways, for example, as 13749264 + 8191044 = 3708^2 + 2862^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21940309) 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 19 ways as a sum of consecutive naturals, for example, 1608 + ... + 6816.

Almost surely, 2^21940308 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 21940308, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30890090).

21940308 is an abundant number, since it is smaller than the sum of its proper divisors (39839872).

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

21940308 is a wasteful number, since it uses less digits than its factorization.

21940308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5238 (or 5227 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21940308 is about 4684.0482491110. The cubic root of 21940308 is about 279.9502802874.

The spelling of 21940308 in words is "twenty-one million, nine hundred forty thousand, three hundred eight".