31678018 has 4 divisors (see below), whose sum is σ = 47517030. Its totient is φ = 15839008.

The previous prime is 31677983. The next prime is 31678019. The reversal of 31678018 is 81087613.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81087613 = 1607 ⋅50459.

It can be written as a sum of positive squares in only one way, i.e., 29127609 + 2550409 = 5397^2 + 1597^2 .

It is not an unprimeable number, because it can be changed into a prime (31678019) 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, 7919503 + ... + 7919506.

Almost surely, 2^31678018 is an apocalyptic number.

31678018 is a deficient number, since it is larger than the sum of its proper divisors (15839012).

31678018 is a wasteful number, since it uses less digits than its factorization.

31678018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15839011.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 31678018 is about 5628.3228407759. The cubic root of 31678018 is about 316.4117968924.

The spelling of 31678018 in words is "thirty-one million, six hundred seventy-eight thousand, eighteen".