42039991 has 6 divisors (see below), whose sum is σ = 48903720. Its totient is φ = 36034236.

The previous prime is 42039967. The next prime is 42040007. The reversal of 42039991 is 19993024.

It is not a de Polignac number, because 42039991 - 2⁷ = 42039863 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 42039991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42039901) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 428931 + ... + 429028.

It is an arithmetic number, because the mean of its divisors is an integer number (8150620).

Almost surely, 2^42039991 is an apocalyptic number.

42039991 is a deficient number, since it is larger than the sum of its proper divisors (6863729).

42039991 is an equidigital number, since it uses as much as digits as its factorization.

42039991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 857973 (or 857966 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 42039991 is about 6483.8253369442. The cubic root of 42039991 is about 347.7129547146.

The spelling of 42039991 in words is "forty-two million, thirty-nine thousand, nine hundred ninety-one".