21315180 has 48 divisors (see below), whose sum is σ = 59883264. Its totient is φ = 5664960.

The previous prime is 21315167. The next prime is 21315187. The reversal of 21315180 is 8151312.

It is not an unprimeable number, because it can be changed into a prime (21315187) 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 15 ways as a sum of consecutive naturals, for example, 33465 + ... + 34095.

It is an arithmetic number, because the mean of its divisors is an integer number (1247568).

Almost surely, 2^21315180 is an apocalyptic number.

21315180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21315180 is an abundant number, since it is smaller than the sum of its proper divisors (38568084).

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

21315180 is a wasteful number, since it uses less digits than its factorization.

21315180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1206 (or 1204 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 21315180 is about 4616.8365793041. The cubic root of 21315180 is about 277.2658198014.

Adding to 21315180 its reverse (8151312), we get a palindrome (29466492).

The spelling of 21315180 in words is "twenty-one million, three hundred fifteen thousand, one hundred eighty".