21337920 has 168 divisors, whose sum is σ = 76078080. Its totient is φ = 5483520.

The previous prime is 21337913. The next prime is 21337957. The reversal of 21337920 is 2973312.

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, 89161 + ... + 89399.

Almost surely, 2^21337920 is an apocalyptic number.

21337920 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 21337920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38039040).

21337920 is an abundant number, since it is smaller than the sum of its proper divisors (54740160).

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

21337920 is a wasteful number, since it uses less digits than its factorization.

21337920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 27.

The square root of 21337920 is about 4619.2986480634. The cubic root of 21337920 is about 277.3643846725.

The spelling of 21337920 in words is "twenty-one million, three hundred thirty-seven thousand, nine hundred twenty".