21795280 has 80 divisors (see below), whose sum is σ = 57496320. Its totient is φ = 7617024.

The previous prime is 21795259. The next prime is 21795289. The reversal of 21795280 is 8259712.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21795289) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19209 + ... + 20311.

It is an arithmetic number, because the mean of its divisors is an integer number (718704).

Almost surely, 2^21795280 is an apocalyptic number.

21795280 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 21795280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28748160).

21795280 is an abundant number, since it is smaller than the sum of its proper divisors (35701040).

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

21795280 is a wasteful number, since it uses less digits than its factorization.

21795280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1148 (or 1142 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 21795280 is about 4668.5415281435. The cubic root of 21795280 is about 279.3320814678.

The spelling of 21795280 in words is "twenty-one million, seven hundred ninety-five thousand, two hundred eighty".