39991918 has 4 divisors (see below), whose sum is σ = 59987880. Its totient is φ = 19995958.

The previous prime is 39991909. The next prime is 39991921. The reversal of 39991918 is 81919993.

39991918 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

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 as a sum of consecutive naturals, namely, 9997978 + ... + 9997981.

It is an arithmetic number, because the mean of its divisors is an integer number (14996970).

Almost surely, 2^39991918 is an apocalyptic number.

39991918 is a deficient number, since it is larger than the sum of its proper divisors (19995962).

39991918 is a wasteful number, since it uses less digits than its factorization.

39991918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19995961.

The product of its digits is 157464, while the sum is 49.

The square root of 39991918 is about 6323.9163498579. The cubic root of 39991918 is about 341.9721544079.

It can be divided in two parts, 3 and 9991918, that added together give a square (9991921 = 3161²).

The spelling of 39991918 in words is "thirty-nine million, nine hundred ninety-one thousand, nine hundred eighteen".