21451680360 has 384 divisors, whose sum is σ = 79248274560. Its totient is φ = 5175705600.

The previous prime is 21451680337. The next prime is 21451680373. The reversal of 21451680360 is 6308615412.

It is a happy number.

21451680360 is a `hidden beast` number, since 2 + 1 + 4 + 516 + 80 + 3 + 60 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 33465640 + ... + 33466280.

It is an arithmetic number, because the mean of its divisors is an integer number (206375715).

Almost surely, 2^21451680360 is an apocalyptic number.

21451680360 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 21451680360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39624137280).

21451680360 is an abundant number, since it is smaller than the sum of its proper divisors (57796594200).

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

21451680360 is a wasteful number, since it uses less digits than its factorization.

21451680360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 991 (or 975 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 21451680360 in words is "twenty-one billion, four hundred fifty-one million, six hundred eighty thousand, three hundred sixty".