21369960 has 128 divisors (see below), whose sum is σ = 72921600. Its totient is φ = 5564160.

The previous prime is 21369949. The next prime is 21369989. The reversal of 21369960 is 6996312.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 50550 + ... + 50970.

It is an arithmetic number, because the mean of its divisors is an integer number (569700).

Almost surely, 2^21369960 is an apocalyptic number.

21369960 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 21369960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36460800).

21369960 is an abundant number, since it is smaller than the sum of its proper divisors (51551640).

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

21369960 is a wasteful number, since it uses less digits than its factorization.

21369960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 488 (or 478 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 21369960 is about 4622.7654061179. The cubic root of 21369960 is about 277.5031409433.

The spelling of 21369960 in words is "twenty-one million, three hundred sixty-nine thousand, nine hundred sixty".