17821380816 has 60 divisors (see below), whose sum is σ = 50000904772. Its totient is φ = 5925477888.

The previous prime is 17821380803. The next prime is 17821380883. The reversal of 17821380816 is 61808312871.

It is a happy number.

17821380816 is a `hidden beast` number, since 178 + 21 + 380 + 81 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15152625216 + 2668755600 = 123096^2 + 51660^2 .

It is a super-2 number, since 2×17821380816² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 98701 + ... + 213036.

Almost surely, 2^17821380816 is an apocalyptic number.

17821380816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

17821380816 is an abundant number, since it is smaller than the sum of its proper divisors (32179523956).

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

17821380816 is a wasteful number, since it uses less digits than its factorization.

17821380816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312148 (or 312139 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The spelling of 17821380816 in words is "seventeen billion, eight hundred twenty-one million, three hundred eighty thousand, eight hundred sixteen".