31401221 has 2 divisors, whose sum is σ = 31401222. Its totient is φ = 31401220.

The previous prime is 31401211. The next prime is 31401239. The reversal of 31401221 is 12210413.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19936225 + 11464996 = 4465^2 + 3386^2 .

It is a cyclic number.

It is not a de Polignac number, because 31401221 - 2¹⁸ = 31139077 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31401196 and 31401205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31401211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15700610 + 15700611.

It is an arithmetic number, because the mean of its divisors is an integer number (15700611).

Almost surely, 2^31401221 is an apocalyptic number.

It is an amenable number.

31401221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31401221 is an equidigital number, since it uses as much as digits as its factorization.

31401221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 31401221 is about 5603.6792377865. The cubic root of 31401221 is about 315.4875158625.

Adding to 31401221 its reverse (12210413), we get a palindrome (43611634).

The spelling of 31401221 in words is "thirty-one million, four hundred one thousand, two hundred twenty-one".