31442381 has 2 divisors, whose sum is σ = 31442382. Its totient is φ = 31442380.

The previous prime is 31442377. The next prime is 31442413. The reversal of 31442381 is 18324413.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24098281 + 7344100 = 4909^2 + 2710^2 .

It is a cyclic number.

It is not a de Polignac number, because 31442381 - 2² = 31442377 is a prime.

It is a super-2 number, since 2×31442381² = 1977246645898322, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31442381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31442681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15721190 + 15721191.

It is an arithmetic number, because the mean of its divisors is an integer number (15721191).

Almost surely, 2^31442381 is an apocalyptic number.

It is an amenable number.

31442381 is a deficient number, since it is larger than the sum of its proper divisors (1).

31442381 is an equidigital number, since it uses as much as digits as its factorization.

31442381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 26.

The square root of 31442381 is about 5607.3506221744. The cubic root of 31442381 is about 315.6253002775.

Adding to 31442381 its reverse (18324413), we get a palindrome (49766794).

The spelling of 31442381 in words is "thirty-one million, four hundred forty-two thousand, three hundred eighty-one".