21161760 has 48 divisors (see below), whose sum is σ = 66661056. Its totient is φ = 5643008.

The previous prime is 21161737. The next prime is 21161761. The reversal of 21161760 is 6716112.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21161760.

It is not an unprimeable number, because it can be changed into a prime (21161761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21564 + ... + 22523.

It is an arithmetic number, because the mean of its divisors is an integer number (1388772).

Almost surely, 2^21161760 is an apocalyptic number.

21161760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21161760 is an abundant number, since it is smaller than the sum of its proper divisors (45499296).

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

21161760 is a wasteful number, since it uses less digits than its factorization.

21161760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44105 (or 44097 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21161760 is about 4600.1913003700. The cubic root of 21161760 is about 276.5989931416.

Adding to 21161760 its reverse (6716112), we get a palindrome (27877872).

The spelling of 21161760 in words is "twenty-one million, one hundred sixty-one thousand, seven hundred sixty".