21292380 has 72 divisors (see below), whose sum is σ = 66830400. Its totient is φ = 5480832.

The previous prime is 21292367. The next prime is 21292391. The reversal of 21292380 is 8329212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3181 + ... + 7259.

It is an arithmetic number, because the mean of its divisors is an integer number (928200).

Almost surely, 2^21292380 is an apocalyptic number.

21292380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21292380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33415200).

21292380 is an abundant number, since it is smaller than the sum of its proper divisors (45538020).

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

21292380 is a wasteful number, since it uses less digits than its factorization.

21292380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4123 (or 4118 counting only the distinct ones).

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

The square root of 21292380 is about 4614.3666954415. The cubic root of 21292380 is about 277.1669244595.

The spelling of 21292380 in words is "twenty-one million, two hundred ninety-two thousand, three hundred eighty".