31000005 has 12 divisors (see below), whose sum is σ = 53733420. Its totient is φ = 16533312.

The previous prime is 31000003. The next prime is 31000063. The reversal of 31000005 is 50000013.

It can be written as a sum of positive squares in 2 ways, for example, as 3814209 + 27185796 = 1953^2 + 5214^2 .

It is not a de Polignac number, because 31000005 - 2¹ = 31000003 is a prime.

It is a super-2 number, since 2×31000005² = 1922000620000050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31000003) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 344400 + ... + 344489.

It is an arithmetic number, because the mean of its divisors is an integer number (4477785).

Almost surely, 2^31000005 is an apocalyptic number.

It is an amenable number.

31000005 is a deficient number, since it is larger than the sum of its proper divisors (22733415).

31000005 is a wasteful number, since it uses less digits than its factorization.

31000005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 688900 (or 688897 counting only the distinct ones).

The product of its (nonzero) digits is 15, while the sum is 9.

The square root of 31000005 is about 5567.7648118433. The cubic root of 31000005 is about 314.1380821283.

Adding to 31000005 its reverse (50000013), we get a palindrome (81000018).

The spelling of 31000005 in words is "thirty-one million, five", and thus it is an aban number and an uban number.