21246280 has 64 divisors (see below), whose sum is σ = 52747200. Its totient is φ = 7637760.

The previous prime is 21246271. The next prime is 21246287. The reversal of 21246280 is 8264212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21246287) 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, 47739 + ... + 48181.

It is an arithmetic number, because the mean of its divisors is an integer number (824175).

Almost surely, 2^21246280 is an apocalyptic number.

21246280 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 21246280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26373600).

21246280 is an abundant number, since it is smaller than the sum of its proper divisors (31500920).

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

21246280 is a wasteful number, since it uses less digits than its factorization.

21246280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574 (or 570 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 21246280 is about 4609.3687203347. The cubic root of 21246280 is about 276.9667491269.

The spelling of 21246280 in words is "twenty-one million, two hundred forty-six thousand, two hundred eighty".