21718167660 has 192 divisors, whose sum is σ = 77554713600. Its totient is φ = 4942646784.

The previous prime is 21718167649. The next prime is 21718167661. The reversal of 21718167660 is 6676181712.

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

It is not an unprimeable number, because it can be changed into a prime (21718167661) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 868411 + ... + 893069.

It is an arithmetic number, because the mean of its divisors is an integer number (403930800).

Almost surely, 2^21718167660 is an apocalyptic number.

21718167660 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 21718167660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38777356800).

21718167660 is an abundant number, since it is smaller than the sum of its proper divisors (55836545940).

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

21718167660 is a wasteful number, since it uses less digits than its factorization.

21718167660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24917 (or 24909 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The spelling of 21718167660 in words is "twenty-one billion, seven hundred eighteen million, one hundred sixty-seven thousand, six hundred sixty".