21012480 has 224 divisors, whose sum is σ = 78638400. Its totient is φ = 5308416.

The previous prime is 21012457. The next prime is 21012503. The reversal of 21012480 is 8421012.

It is an interprime number because it is at equal distance from previous prime (21012457) and next prime (21012503).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a zygodrome in base 4.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1105911 + ... + 1105929.

Almost surely, 2^21012480 is an apocalyptic number.

21012480 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 21012480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39319200).

21012480 is an abundant number, since it is smaller than the sum of its proper divisors (57625920).

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

21012480 is an equidigital number, since it uses as much as digits as its factorization.

21012480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59 (or 29 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 21012480 is about 4583.9371723443. The cubic root of 21012480 is about 275.9470597894.

Adding to 21012480 its reverse (8421012), we get a palindrome (29433492).

The spelling of 21012480 in words is "twenty-one million, twelve thousand, four hundred eighty".