17981820864 has 252 divisors, whose sum is σ = 60246548544. Its totient is φ = 5112834048.

The previous prime is 17981820841. The next prime is 17981820919. The reversal of 17981820864 is 46802818971.

It is a tau number, because it is divible by the number of its divisors (252).

It is a self number, because there is not a number n which added to its sum of digits gives 17981820864.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 6292524 + ... + 6295380.

Almost surely, 2^17981820864 is an apocalyptic number.

17981820864 is a gapful number since it is divisible by the number (14) 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 17981820864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30123274272).

17981820864 is an abundant number, since it is smaller than the sum of its proper divisors (42264727680).

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

17981820864 is a wasteful number, since it uses less digits than its factorization.

17981820864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3112 (or 3092 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 54.

The spelling of 17981820864 in words is "seventeen billion, nine hundred eighty-one million, eight hundred twenty thousand, eight hundred sixty-four".