31439978 has 8 divisors (see below), whose sum is σ = 47202372. Its totient is φ = 15705856.

The previous prime is 31439977. The next prime is 31440001. The reversal of 31439978 is 87993413.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 31326409 + 113569 = 5597^2 + 337^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (31439977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4025 + ... + 8892.

Almost surely, 2^31439978 is an apocalyptic number.

31439978 is a deficient number, since it is larger than the sum of its proper divisors (15762394).

31439978 is a wasteful number, since it uses less digits than its factorization.

31439978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14136.

The product of its digits is 163296, while the sum is 44.

The square root of 31439978 is about 5607.1363457651. The cubic root of 31439978 is about 315.6172594645.

The spelling of 31439978 in words is "thirty-one million, four hundred thirty-nine thousand, nine hundred seventy-eight".