21365760 has 176 divisors, whose sum is σ = 74281536. Its totient is φ = 5210112.

The previous prime is 21365759. The next prime is 21365767. The reversal of 21365760 is 6756312.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21365767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 199627 + ... + 199733.

Almost surely, 2^21365760 is an apocalyptic number.

21365760 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 21365760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37140768).

21365760 is an abundant number, since it is smaller than the sum of its proper divisors (52915776).

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

21365760 is a wasteful number, since it uses less digits than its factorization.

21365760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 21365760 is about 4622.3111102564. The cubic root of 21365760 is about 277.4849598212.

The spelling of 21365760 in words is "twenty-one million, three hundred sixty-five thousand, seven hundred sixty".