31405223 has 4 divisors (see below), whose sum is σ = 31543800. Its totient is φ = 31266648.

The previous prime is 31405219. The next prime is 31405277. The reversal of 31405223 is 32250413.

It is a happy number.

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 31405223 - 2² = 31405219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31405195 and 31405204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31405123) 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, 68948 + ... + 69401.

It is an arithmetic number, because the mean of its divisors is an integer number (7885950).

Almost surely, 2^31405223 is an apocalyptic number.

31405223 is a deficient number, since it is larger than the sum of its proper divisors (138577).

31405223 is a wasteful number, since it uses less digits than its factorization.

31405223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138576.

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 31405223 is about 5604.0363132300. The cubic root of 31405223 is about 315.5009179677.

Adding to 31405223 its reverse (32250413), we get a palindrome (63655636).

The spelling of 31405223 in words is "thirty-one million, four hundred five thousand, two hundred twenty-three".