21719280 has 160 divisors (see below), whose sum is σ = 77495040. Its totient is φ = 4976640.

The previous prime is 21719279. The next prime is 21719287. The reversal of 21719280 is 8291712.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21719287) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 49944 + ... + 50376.

It is an arithmetic number, because the mean of its divisors is an integer number (484344).

Almost surely, 2^21719280 is an apocalyptic number.

21719280 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 21719280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38747520).

21719280 is an abundant number, since it is smaller than the sum of its proper divisors (55775760).

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

21719280 is a wasteful number, since it uses less digits than its factorization.

21719280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479 (or 473 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 21719280 is about 4660.3948330587. The cubic root of 21719280 is about 279.0070269681.

The spelling of 21719280 in words is "twenty-one million, seven hundred nineteen thousand, two hundred eighty".