21165480 has 192 divisors, whose sum is σ = 81095040. Its totient is φ = 4686336.

The previous prime is 21165479. The next prime is 21165481. The reversal of 21165480 is 8456112.

21165480 = 242² + 243² + ... + 426².

21165480 is a `hidden beast` number, since 2 + 1 + 1 + 654 + 8 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21165479) and next prime (21165481).

It is not an unprimeable number, because it can be changed into a prime (21165481) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 93127 + ... + 93353.

It is an arithmetic number, because the mean of its divisors is an integer number (422370).

Almost surely, 2^21165480 is an apocalyptic number.

21165480 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 21165480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40547520).

21165480 is an abundant number, since it is smaller than the sum of its proper divisors (59929560).

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

21165480 is a wasteful number, since it uses less digits than its factorization.

21165480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 281 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 21165480 is about 4600.5956136135. The cubic root of 21165480 is about 276.6151998586.

The spelling of 21165480 in words is "twenty-one million, one hundred sixty-five thousand, four hundred eighty".