21830280 has 32 divisors (see below), whose sum is σ = 65491200. Its totient is φ = 5821376.

The previous prime is 21830279. The next prime is 21830287. The reversal of 21830280 is 8203812.

It is a super-2 number, since 2×21830280² = 953122249756800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21830280.

It is not an unprimeable number, because it can be changed into a prime (21830287) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90840 + ... + 91079.

It is an arithmetic number, because the mean of its divisors is an integer number (2046600).

Almost surely, 2^21830280 is an apocalyptic number.

21830280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21830280 is an abundant number, since it is smaller than the sum of its proper divisors (43660920).

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

21830280 is a wasteful number, since it uses less digits than its factorization.

21830280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181933 (or 181929 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21830280 is about 4672.2885184886. The cubic root of 21830280 is about 279.4815235220.

The spelling of 21830280 in words is "twenty-one million, eight hundred thirty thousand, two hundred eighty".