31138217 has 8 divisors (see below), whose sum is σ = 34017312. Its totient is φ = 28267200.

The previous prime is 31138213. The next prime is 31138249. The reversal of 31138217 is 71283113.

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 31138217 - 2² = 31138213 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31138213) 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 in 7 ways as a sum of consecutive naturals, for example, 8417 + ... + 11537.

It is an arithmetic number, because the mean of its divisors is an integer number (4252164).

Almost surely, 2^31138217 is an apocalyptic number.

It is an amenable number.

31138217 is a deficient number, since it is larger than the sum of its proper divisors (2879095).

31138217 is a wasteful number, since it uses less digits than its factorization.

31138217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4039.

The product of its digits is 1008, while the sum is 26.

The square root of 31138217 is about 5580.1628112448. The cubic root of 31138217 is about 314.6042464273.

Subtracting 31138217 from its reverse (71283113), we obtain a square (40144896 = 6336²).

The spelling of 31138217 in words is "thirty-one million, one hundred thirty-eight thousand, two hundred seventeen".