21451122660 has 96 divisors (see below), whose sum is σ = 65755533312. Its totient is φ = 5181851520.

The previous prime is 21451122659. The next prime is 21451122673. The reversal of 21451122660 is 6622115412.

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 129357 + ... + 244203.

It is an arithmetic number, because the mean of its divisors is an integer number (684953472).

Almost surely, 2^21451122660 is an apocalyptic number.

21451122660 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 21451122660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32877766656).

21451122660 is an abundant number, since it is smaller than the sum of its proper divisors (44304410652).

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

21451122660 is a wasteful number, since it uses less digits than its factorization.

21451122660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115153 (or 115151 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The spelling of 21451122660 in words is "twenty-one billion, four hundred fifty-one million, one hundred twenty-two thousand, six hundred sixty".