21098856660 has 384 divisors, whose sum is σ = 74104934400. Its totient is φ = 4377784320.

The previous prime is 21098856613. The next prime is 21098856677. The reversal of 21098856660 is 6665889012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 19303074 + ... + 19304166.

It is an arithmetic number, because the mean of its divisors is an integer number (192981600).

Almost surely, 2^21098856660 is an apocalyptic number.

21098856660 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 21098856660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37052467200).

21098856660 is an abundant number, since it is smaller than the sum of its proper divisors (53006077740).

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

21098856660 is a wasteful number, since it uses less digits than its factorization.

21098856660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1231 (or 1229 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 51.

The spelling of 21098856660 in words is "twenty-one billion, ninety-eight million, eight hundred fifty-six thousand, six hundred sixty".