31309994 has 4 divisors (see below), whose sum is σ = 46964994. Its totient is φ = 15654996.

The previous prime is 31309987. The next prime is 31310003. The reversal of 31309994 is 49990313.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 49990313 = 449 ⋅111337.

It can be written as a sum of positive squares in only one way, i.e., 20584369 + 10725625 = 4537^2 + 3275^2 .

It is a Curzon number.

It is a nialpdrome in base 13.

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, 7827497 + ... + 7827500.

Almost surely, 2^31309994 is an apocalyptic number.

31309994 is a deficient number, since it is larger than the sum of its proper divisors (15655000).

31309994 is a wasteful number, since it uses less digits than its factorization.

31309994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15654999.

The product of its (nonzero) digits is 26244, while the sum is 38.

The square root of 31309994 is about 5595.5333972732. The cubic root of 31309994 is about 315.1817008303.

The spelling of 31309994 in words is "thirty-one million, three hundred nine thousand, nine hundred ninety-four".