21102860 has 12 divisors (see below), whose sum is σ = 44316048. Its totient is φ = 8441136.

The previous prime is 21102853. The next prime is 21102869. The reversal of 21102860 is 6820112.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1055143 = 21102860 / (2 + 1 + 1 + 0 + 2 + 8 + 6 + 0).

It is not an unprimeable number, because it can be changed into a prime (21102869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 527552 + ... + 527591.

It is an arithmetic number, because the mean of its divisors is an integer number (3693004).

Almost surely, 2^21102860 is an apocalyptic number.

21102860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21102860 is an abundant number, since it is smaller than the sum of its proper divisors (23213188).

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

21102860 is a wasteful number, since it uses less digits than its factorization.

21102860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1055152 (or 1055150 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 21102860 is about 4593.7849318400. The cubic root of 21102860 is about 276.3421332977.

Adding to 21102860 its reverse (6820112), we get a palindrome (27922972).

The spelling of 21102860 in words is "twenty-one million, one hundred two thousand, eight hundred sixty".