21198660 has 96 divisors (see below), whose sum is σ = 71850240. Its totient is φ = 4558848.

The previous prime is 21198631. The next prime is 21198673. The reversal of 21198660 is 6689112.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5656 + ... + 8624.

It is an arithmetic number, because the mean of its divisors is an integer number (748440).

Almost surely, 2^21198660 is an apocalyptic number.

21198660 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 21198660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35925120).

21198660 is an abundant number, since it is smaller than the sum of its proper divisors (50651580).

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

21198660 is a wasteful number, since it uses less digits than its factorization.

21198660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3005 (or 3003 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 21198660 is about 4604.2002562877. The cubic root of 21198660 is about 276.7596693832.

The spelling of 21198660 in words is "twenty-one million, one hundred ninety-eight thousand, six hundred sixty".