21181180 has 12 divisors (see below), whose sum is σ = 44480520. Its totient is φ = 8472464.

The previous prime is 21181157. The next prime is 21181189. The reversal of 21181180 is 8118112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21181189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 529510 + ... + 529549.

It is an arithmetic number, because the mean of its divisors is an integer number (3706710).

Almost surely, 2^21181180 is an apocalyptic number.

21181180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21181180 is an abundant number, since it is smaller than the sum of its proper divisors (23299340).

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

21181180 is a wasteful number, since it uses less digits than its factorization.

21181180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1059068 (or 1059066 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 22.

The square root of 21181180 is about 4602.3015981137. The cubic root of 21181180 is about 276.6835782633.

Adding to 21181180 its reverse (8118112), we get a palindrome (29299292).

The spelling of 21181180 in words is "twenty-one million, one hundred eighty-one thousand, one hundred eighty".