21499081560 has 960 divisors, whose sum is σ = 86206982400. Its totient is φ = 4790016000.

The previous prime is 21499081553. The next prime is 21499081561. The reversal of 21499081560 is 6518099412.

21499081560 is a `hidden beast` number, since 2 + 1 + 4 + 9 + 9 + 0 + 81 + 560 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21499081561) by changing a digit.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 352443930 + ... + 352443990.

It is an arithmetic number, because the mean of its divisors is an integer number (89798940).

Almost surely, 2^21499081560 is an apocalyptic number.

21499081560 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 21499081560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43103491200).

21499081560 is an abundant number, since it is smaller than the sum of its proper divisors (64707900840).

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

21499081560 is a wasteful number, since it uses less digits than its factorization.

21499081560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166 (or 142 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 21499081560 in words is "twenty-one billion, four hundred ninety-nine million, eighty-one thousand, five hundred sixty".