21899280 has 80 divisors (see below), whose sum is σ = 73120320. Its totient is φ = 5389824.

The previous prime is 21899279. The next prime is 21899303. The reversal of 21899280 is 8299812.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 390 + ... + 6629.

It is an arithmetic number, because the mean of its divisors is an integer number (914004).

Almost surely, 2^21899280 is an apocalyptic number.

21899280 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 21899280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36560160).

21899280 is an abundant number, since it is smaller than the sum of its proper divisors (51221040).

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

21899280 is a wasteful number, since it uses less digits than its factorization.

21899280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7048 (or 7042 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 21899280 is about 4679.6666547950. Note that the first 4 decimals coincide. The cubic root of 21899280 is about 279.7756706608.

The spelling of 21899280 in words is "twenty-one million, eight hundred ninety-nine thousand, two hundred eighty".