21158400 has 240 divisors, whose sum is σ = 76111200. Its totient is φ = 5160960.

The previous prime is 21158377. The next prime is 21158471. The reversal of 21158400 is 485112.

It is a tau number, because it is divible by the number of its divisors (240).

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, 729586 + ... + 729614.

It is an arithmetic number, because the mean of its divisors is an integer number (317130).

Almost surely, 2^21158400 is an apocalyptic number.

21158400 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 21158400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38055600).

21158400 is an abundant number, since it is smaller than the sum of its proper divisors (54952800).

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

21158400 is a wasteful number, since it uses less digits than its factorization.

21158400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 21158400 is about 4599.8260836688. The cubic root of 21158400 is about 276.5843531840.

The spelling of 21158400 in words is "twenty-one million, one hundred fifty-eight thousand, four hundred".