31523206381 has 2 divisors, whose sum is σ = 31523206382. Its totient is φ = 31523206380.

The previous prime is 31523206289. The next prime is 31523206399. The reversal of 31523206381 is 18360232513.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31488502500 + 34703881 = 177450^2 + 5891^2 .

It is a cyclic number.

It is not a de Polignac number, because 31523206381 - 2¹¹ = 31523204333 is a prime.

It is a super-2 number, since 2×31523206381² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31523200381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15761603190 + 15761603191.

It is an arithmetic number, because the mean of its divisors is an integer number (15761603191).

Almost surely, 2^31523206381 is an apocalyptic number.

It is an amenable number.

31523206381 is a deficient number, since it is larger than the sum of its proper divisors (1).

31523206381 is an equidigital number, since it uses as much as digits as its factorization.

31523206381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 34.

Adding to 31523206381 its reverse (18360232513), we get a palindrome (49883438894).

The spelling of 31523206381 in words is "thirty-one billion, five hundred twenty-three million, two hundred six thousand, three hundred eighty-one".