31222021 has 2 divisors, whose sum is σ = 31222022. Its totient is φ = 31222020.

The previous prime is 31221977. The next prime is 31222091. The reversal of 31222021 is 12022213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18369796 + 12852225 = 4286^2 + 3585^2 .

It is a cyclic number.

It is not a de Polignac number, because 31222021 - 2¹⁵ = 31189253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31221992 and 31222010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31222091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15611010 + 15611011.

It is an arithmetic number, because the mean of its divisors is an integer number (15611011).

Almost surely, 2^31222021 is an apocalyptic number.

It is an amenable number.

31222021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31222021 is an equidigital number, since it uses as much as digits as its factorization.

31222021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 31222021 is about 5587.6668655173. Note that the first 3 decimals coincide. The cubic root of 31222021 is about 314.8862308556.

Adding to 31222021 its reverse (12022213), we get a palindrome (43244234).

The spelling of 31222021 in words is "thirty-one million, two hundred twenty-two thousand, twenty-one".