31219121 has 2 divisors, whose sum is σ = 31219122. Its totient is φ = 31219120.

The previous prime is 31219087. The next prime is 31219169. The reversal of 31219121 is 12191213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31192225 + 26896 = 5585^2 + 164^2 .

It is an emirp because it is prime and its reverse (12191213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31219121 - 2⁶ = 31219057 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31219093 and 31219102.

It is not a weakly prime, because it can be changed into another prime (31219621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15609560 + 15609561.

It is an arithmetic number, because the mean of its divisors is an integer number (15609561).

Almost surely, 2^31219121 is an apocalyptic number.

It is an amenable number.

31219121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31219121 is an equidigital number, since it uses as much as digits as its factorization.

31219121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108, while the sum is 20.

The square root of 31219121 is about 5587.4073594110. The cubic root of 31219121 is about 314.8764813443.

The spelling of 31219121 in words is "thirty-one million, two hundred nineteen thousand, one hundred twenty-one".