31378321 has 8 divisors (see below), whose sum is σ = 33836264. Its totient is φ = 28926720.

The previous prime is 31378307. The next prime is 31378327. The reversal of 31378321 is 12387313.

It can be written as a sum of positive squares in 4 ways, for example, as 1073296 + 30305025 = 1036^2 + 5505^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 31378321 - 2¹⁵ = 31345553 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31378321.

It is not an unprimeable number, because it can be changed into a prime (31378327) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15931 + ... + 17791.

It is an arithmetic number, because the mean of its divisors is an integer number (4229533).

Almost surely, 2^31378321 is an apocalyptic number.

It is an amenable number.

31378321 is a deficient number, since it is larger than the sum of its proper divisors (2457943).

31378321 is a wasteful number, since it uses less digits than its factorization.

31378321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3171.

The product of its digits is 3024, while the sum is 28.

The square root of 31378321 is about 5601.6355647257. The cubic root of 31378321 is about 315.4108052459.

The spelling of 31378321 in words is "thirty-one million, three hundred seventy-eight thousand, three hundred twenty-one".