31405143221 has 2 divisors, whose sum is σ = 31405143222. Its totient is φ = 31405143220.

The previous prime is 31405143179. The next prime is 31405143251. The reversal of 31405143221 is 12234150413.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25443759121 + 5961384100 = 159511^2 + 77210^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31405143221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31405143251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15702571610 + 15702571611.

It is an arithmetic number, because the mean of its divisors is an integer number (15702571611).

Almost surely, 2^31405143221 is an apocalyptic number.

It is an amenable number.

31405143221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31405143221 is an equidigital number, since it uses as much as digits as its factorization.

31405143221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 26.

Adding to 31405143221 its reverse (12234150413), we get a palindrome (43639293634).

The spelling of 31405143221 in words is "thirty-one billion, four hundred five million, one hundred forty-three thousand, two hundred twenty-one".