31402331221 has 2 divisors, whose sum is σ = 31402331222. Its totient is φ = 31402331220.

The previous prime is 31402331209. The next prime is 31402331291. The reversal of 31402331221 is 12213320413.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26900592196 + 4501739025 = 164014^2 + 67095^2 .

It is a cyclic number.

It is not a de Polignac number, because 31402331221 - 2¹⁷ = 31402200149 is a prime.

It is a super-2 number, since 2×31402331221² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31402331192 and 31402331201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31402331291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15701165610 + 15701165611.

It is an arithmetic number, because the mean of its divisors is an integer number (15701165611).

Almost surely, 2^31402331221 is an apocalyptic number.

It is an amenable number.

31402331221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31402331221 is an equidigital number, since it uses as much as digits as its factorization.

31402331221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 22.

Adding to 31402331221 its reverse (12213320413), we get a palindrome (43615651634).

The spelling of 31402331221 in words is "thirty-one billion, four hundred two million, three hundred thirty-one thousand, two hundred twenty-one".