42081997 has 4 divisors (see below), whose sum is σ = 42134076. Its totient is φ = 42029920.

The previous prime is 42081943. The next prime is 42082003. The reversal of 42081997 is 79918024.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6869641 + 35212356 = 2621^2 + 5934^2 .

It is a cyclic number.

It is not a de Polignac number, because 42081997 - 2⁷ = 42081869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42081917) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24808 + ... + 26449.

It is an arithmetic number, because the mean of its divisors is an integer number (10533519).

Almost surely, 2^42081997 is an apocalyptic number.

It is an amenable number.

42081997 is a deficient number, since it is larger than the sum of its proper divisors (52079).

42081997 is an equidigital number, since it uses as much as digits as its factorization.

42081997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52078.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 42081997 is about 6487.0638196337. The cubic root of 42081997 is about 347.8287267687.

The spelling of 42081997 in words is "forty-two million, eighty-one thousand, nine hundred ninety-seven".