21518861760 has 560 divisors, whose sum is σ = 84760929792. Its totient is φ = 5138380800.

The previous prime is 21518861753. The next prime is 21518861779. The reversal of 21518861760 is 6716881512.

21518861760 is a `hidden beast` number, since 2 + 1 + 518 + 8 + 61 + 76 + 0 = 666.

It is a super-2 number, since 2×21518861760² (a number of 21 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 20242989 + ... + 20244051.

Almost surely, 2^21518861760 is an apocalyptic number.

21518861760 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 21518861760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42380464896).

21518861760 is an abundant number, since it is smaller than the sum of its proper divisors (63242068032).

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

21518861760 is a wasteful number, since it uses less digits than its factorization.

21518861760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1174 (or 1155 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 21518861760 in words is "twenty-one billion, five hundred eighteen million, eight hundred sixty-one thousand, seven hundred sixty".