191020042 has 8 divisors (see below), whose sum is σ = 296410500. Its totient is φ = 92216544.

The previous prime is 191020009. The next prime is 191020073. The reversal of 191020042 is 240020191.

It is a Cunningham number, because it is equal to 13821²+1.

It can be written as a sum of positive squares in 2 ways, for example, as 191020041 + 1 = 13821^2 + 1^2 .

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

It is a super-3 number, since 3×191020042³ (a number of 26 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1646667 + ... + 1646782.

Almost surely, 2^191020042 is an apocalyptic number.

191020042 is a deficient number, since it is larger than the sum of its proper divisors (105390458).

191020042 is a wasteful number, since it uses less digits than its factorization.

191020042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3293480.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 191020042 is about 13821.0000361768. Note that the first 4 decimals coincide. The cubic root of 191020042 is about 575.9166646573.

It can be divided in two parts, 1910 and 20042, that added together give a cube (21952 = 28³).

The spelling of 191020042 in words is "one hundred ninety-one million, twenty thousand, forty-two".