991198019902 has 8 divisors (see below), whose sum is σ = 1486818636912. Its totient is φ = 495591807600.

The previous prime is 991198019873. The next prime is 991198019947. The reversal of 991198019902 is 209910891199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3427474 + ... + 3705397.

It is an arithmetic number, because the mean of its divisors is an integer number (185852329614).

Almost surely, 2^991198019902 is an apocalyptic number.

991198019902 is a deficient number, since it is larger than the sum of its proper divisors (495620617010).

991198019902 is a wasteful number, since it uses less digits than its factorization.

991198019902 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7202354.

The product of its (nonzero) digits is 944784, while the sum is 58.

The spelling of 991198019902 in words is "nine hundred ninety-one billion, one hundred ninety-eight million, nineteen thousand, nine hundred two".