31861145 has 8 divisors (see below), whose sum is σ = 40482504. Its totient is φ = 23989504.

The previous prime is 31861133. The next prime is 31861147. The reversal of 31861145 is 54116813.

31861145 = 1361² + 1362² + ... + 1377².

It can be written as a sum of positive squares in 4 ways, for example, as 6901129 + 24960016 = 2627^2 + 4996^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31861145 is a prime.

It is a super-2 number, since 2×31861145² = 2030265121422050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31861147) 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 7 ways as a sum of consecutive naturals, for example, 187334 + ... + 187503.

It is an arithmetic number, because the mean of its divisors is an integer number (5060313).

Almost surely, 2^31861145 is an apocalyptic number.

It is an amenable number.

31861145 is a deficient number, since it is larger than the sum of its proper divisors (8621359).

31861145 is a wasteful number, since it uses less digits than its factorization.

31861145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374859.

The product of its digits is 2880, while the sum is 29.

The square root of 31861145 is about 5644.5677425291. The cubic root of 31861145 is about 317.0203392298.

Adding to 31861145 its reverse (54116813), we get a palindrome (85977958).

The spelling of 31861145 in words is "thirty-one million, eight hundred sixty-one thousand, one hundred forty-five".