31381223 has 4 divisors (see below), whose sum is σ = 32745648. Its totient is φ = 30016800.

The previous prime is 31381213. The next prime is 31381241. The reversal of 31381223 is 32218313.

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

It is a cyclic number.

It is not a de Polignac number, because 31381223 - 2⁶ = 31381159 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 1364401 = 31381223 / (3 + 1 + 3 + 8 + 1 + 2 + 2 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31381213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 682178 + ... + 682223.

It is an arithmetic number, because the mean of its divisors is an integer number (8186412).

Almost surely, 2^31381223 is an apocalyptic number.

31381223 is a deficient number, since it is larger than the sum of its proper divisors (1364425).

31381223 is a wasteful number, since it uses less digits than its factorization.

31381223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1364424.

The product of its digits is 864, while the sum is 23.

The square root of 31381223 is about 5601.8945902257. The cubic root of 31381223 is about 315.4205284551.

Adding to 31381223 its reverse (32218313), we get a palindrome (63599536).

The spelling of 31381223 in words is "thirty-one million, three hundred eighty-one thousand, two hundred twenty-three".