17990999878 has 16 divisors (see below), whose sum is σ = 28814708736. Its totient is φ = 8404288200.

The previous prime is 17990999849. The next prime is 17990999891. The reversal of 17990999878 is 87899909971.

It is a happy number.

It is a super-2 number, since 2×17990999878² (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 7 ways as a sum of consecutive naturals, for example, 4545798 + ... + 4549753.

It is an arithmetic number, because the mean of its divisors is an integer number (1800919296).

Almost surely, 2^17990999878 is an apocalyptic number.

17990999878 is a deficient number, since it is larger than the sum of its proper divisors (10823708858).

17990999878 is a wasteful number, since it uses less digits than its factorization.

17990999878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9095619.

The product of its (nonzero) digits is 185177664, while the sum is 76.

The spelling of 17990999878 in words is "seventeen billion, nine hundred ninety million, nine hundred ninety-nine thousand, eight hundred seventy-eight".