31221023 has 4 divisors (see below), whose sum is σ = 32297640. Its totient is φ = 30144408.

The previous prime is 31221017. The next prime is 31221041. The reversal of 31221023 is 32012213.

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 31221023 - 2⁸ = 31220767 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31220989 and 31221007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31221523) 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, 538265 + ... + 538322.

It is an arithmetic number, because the mean of its divisors is an integer number (8074410).

Almost surely, 2^31221023 is an apocalyptic number.

31221023 is a deficient number, since it is larger than the sum of its proper divisors (1076617).

31221023 is a wasteful number, since it uses less digits than its factorization.

31221023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1076616.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 31221023 is about 5587.5775609829. The cubic root of 31221023 is about 314.8828757471.

Adding to 31221023 its reverse (32012213), we get a palindrome (63233236).

The spelling of 31221023 in words is "thirty-one million, two hundred twenty-one thousand, twenty-three".