31142281 has 4 divisors (see below), whose sum is σ = 31428100. Its totient is φ = 30856464.

The previous prime is 31142263. The next prime is 31142297. The reversal of 31142281 is 18224113.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 23765625 + 7376656 = 4875^2 + 2716^2 .

It is a cyclic number.

It is not a de Polignac number, because 31142281 - 2¹¹ = 31140233 is a prime.

It is a super-2 number, since 2×31142281² = 1939683331765922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31142231) 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 in 3 ways as a sum of consecutive naturals, for example, 142746 + ... + 142963.

It is an arithmetic number, because the mean of its divisors is an integer number (7857025).

Almost surely, 2^31142281 is an apocalyptic number.

It is an amenable number.

31142281 is a deficient number, since it is larger than the sum of its proper divisors (285819).

31142281 is a wasteful number, since it uses less digits than its factorization.

31142281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285818.

The product of its digits is 384, while the sum is 22.

The square root of 31142281 is about 5580.5269464451. The cubic root of 31142281 is about 314.6179326748.

Adding to 31142281 its reverse (18224113), we get a palindrome (49366394).

The spelling of 31142281 in words is "thirty-one million, one hundred forty-two thousand, two hundred eighty-one".