31123145 has 4 divisors (see below), whose sum is σ = 37347780. Its totient is φ = 24898512.

The previous prime is 31123139. The next prime is 31123151. The reversal of 31123145 is 54132113.

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

It is an interprime number because it is at equal distance from previous prime (31123139) and next prime (31123151).

It can be written as a sum of positive squares in 2 ways, for example, as 21307456 + 9815689 = 4616^2 + 3133^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31123145 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3112310 + ... + 3112319.

It is an arithmetic number, because the mean of its divisors is an integer number (9336945).

Almost surely, 2^31123145 is an apocalyptic number.

It is an amenable number.

31123145 is a deficient number, since it is larger than the sum of its proper divisors (6224635).

31123145 is an equidigital number, since it uses as much as digits as its factorization.

31123145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6224634.

The product of its digits is 360, while the sum is 20.

The square root of 31123145 is about 5578.8121495530. The cubic root of 31123145 is about 314.5534783688.

Adding to 31123145 its reverse (54132113), we get a palindrome (85255258).

The spelling of 31123145 in words is "thirty-one million, one hundred twenty-three thousand, one hundred forty-five".