42091778 has 4 divisors (see below), whose sum is σ = 63137670. Its totient is φ = 21045888.

The previous prime is 42091747. The next prime is 42091781. The reversal of 42091778 is 87719024.

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., 42081169 + 10609 = 6487^2 + 103^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522943 + ... + 10522946.

Almost surely, 2^42091778 is an apocalyptic number.

42091778 is a deficient number, since it is larger than the sum of its proper divisors (21045892).

42091778 is a wasteful number, since it uses less digits than its factorization.

42091778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21045891.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 42091778 is about 6487.8176608163. The cubic root of 42091778 is about 347.8556729648.

The spelling of 42091778 in words is "forty-two million, ninety-one thousand, seven hundred seventy-eight".