21959280 has 120 divisors (see below), whose sum is σ = 84301152. Its totient is φ = 5018112.

The previous prime is 21959279. The next prime is 21959297. The reversal of 21959280 is 8295912.

It is a tau number, because it is divible by the number of its divisors (120).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2862 + ... + 7218.

Almost surely, 2^21959280 is an apocalyptic number.

21959280 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 21959280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42150576).

21959280 is an abundant number, since it is smaller than the sum of its proper divisors (62341872).

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

21959280 is a wasteful number, since it uses less digits than its factorization.

21959280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4383 (or 4374 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 21959280 is about 4686.0729827863. The cubic root of 21959280 is about 280.0309489600.

The spelling of 21959280 in words is "twenty-one million, nine hundred fifty-nine thousand, two hundred eighty".