91604042 has 4 divisors (see below), whose sum is σ = 137406066. Its totient is φ = 45802020.

The previous prime is 91604021. The next prime is 91604047. The reversal of 91604042 is 24040619.

It is a Cunningham number, because it is equal to 9571²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 91604041 + 1 = 9571^2 + 1^2 .

It is not an unprimeable number, because it can be changed into a prime (91604047) by changing a digit.

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 as a sum of consecutive naturals, namely, 22901009 + ... + 22901012.

Almost surely, 2^91604042 is an apocalyptic number.

91604042 is a deficient number, since it is larger than the sum of its proper divisors (45802024).

91604042 is a wasteful number, since it uses less digits than its factorization.

91604042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45802023.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 91604042 is about 9571.0000522411. Note that the first 4 decimals coincide. The cubic root of 91604042 is about 450.7871687334.

The spelling of 91604042 in words is "ninety-one million, six hundred four thousand, forty-two".