198771891 has 16 divisors (see below), whose sum is σ = 268898304. Its totient is φ = 130594464.

The previous prime is 198771841. The next prime is 198771893. The reversal of 198771891 is 198177891.

It is a happy number.

198771891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

198771891 is a nontrivial binomial coefficient, being equal to C(19939, 2).

It is not a de Polignac number, because 198771891 - 2⁶ = 198771827 is a prime.

It is not an unprimeable number, because it can be changed into a prime (198771893) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58156 + ... + 61478.

It is an arithmetic number, because the mean of its divisors is an integer number (16806144).

Almost surely, 2^198771891 is an apocalyptic number.

198771891 is the 19938-th triangular number.

198771891 is a deficient number, since it is larger than the sum of its proper divisors (70126413).

198771891 is a wasteful number, since it uses less digits than its factorization.

198771891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3610.

The product of its digits is 254016, while the sum is 51.

The square root of 198771891 is about 14098.6485522549. The cubic root of 198771891 is about 583.6040849971.

The spelling of 198771891 in words is "one hundred ninety-eight million, seven hundred seventy-one thousand, eight hundred ninety-one".