21242160 has 120 divisors (see below), whose sum is σ = 72172464. Its totient is φ = 5598720.

The previous prime is 21242153. The next prime is 21242191. The reversal of 21242160 is 6124212.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×21242160² = 902458722931200, which contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 117270 + ... + 117450.

Almost surely, 2^21242160 is an apocalyptic number.

21242160 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 21242160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36086232).

21242160 is an abundant number, since it is smaller than the sum of its proper divisors (50930304).

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

21242160 is a wasteful number, since it uses less digits than its factorization.

21242160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363 (or 354 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21242160 is about 4608.9217828034. The cubic root of 21242160 is about 276.9488451805.

Adding to 21242160 its reverse (6124212), we get a palindrome (27366372).

The spelling of 21242160 in words is "twenty-one million, two hundred forty-two thousand, one hundred sixty".