31990394 has 4 divisors (see below), whose sum is σ = 47985594. Its totient is φ = 15995196.

The previous prime is 31990381. The next prime is 31990397. The reversal of 31990394 is 49309913.

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

It can be written as a sum of positive squares in only one way, i.e., 31753225 + 237169 = 5635^2 + 487^2 .

It is not an unprimeable number, because it can be changed into a prime (31990397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7997597 + ... + 7997600.

Almost surely, 2^31990394 is an apocalyptic number.

31990394 is a deficient number, since it is larger than the sum of its proper divisors (15995200).

31990394 is a wasteful number, since it uses less digits than its factorization.

31990394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15995199.

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

The square root of 31990394 is about 5656.0051272961. The cubic root of 31990394 is about 317.4484393508.

The spelling of 31990394 in words is "thirty-one million, nine hundred ninety thousand, three hundred ninety-four".