21178960 has 80 divisors (see below), whose sum is σ = 55121472. Its totient is φ = 7500800.

The previous prime is 21178943. The next prime is 21178987. The reversal of 21178960 is 6987112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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, 35787 + ... + 36373.

Almost surely, 2^21178960 is an apocalyptic number.

21178960 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 21178960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27560736).

21178960 is an abundant number, since it is smaller than the sum of its proper divisors (33942512).

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

21178960 is a wasteful number, since it uses less digits than its factorization.

21178960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652 (or 646 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 21178960 is about 4602.0604081216. The cubic root of 21178960 is about 276.6739115214.

The spelling of 21178960 in words is "twenty-one million, one hundred seventy-eight thousand, nine hundred sixty".