31100213 has 4 divisors (see below), whose sum is σ = 31261548. Its totient is φ = 30938880.

The previous prime is 31100203. The next prime is 31100219. The reversal of 31100213 is 31200113.

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 5466244 + 25633969 = 2338^2 + 5063^2 .

It is a cyclic number.

It is not a de Polignac number, because 31100213 - 2⁴ = 31100197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31100194 and 31100203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31100219) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80378 + ... + 80763.

It is an arithmetic number, because the mean of its divisors is an integer number (7815387).

Almost surely, 2^31100213 is an apocalyptic number.

It is an amenable number.

31100213 is a deficient number, since it is larger than the sum of its proper divisors (161335).

31100213 is a wasteful number, since it uses less digits than its factorization.

31100213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161334.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 31100213 is about 5576.7564945943. The cubic root of 31100213 is about 314.4762034799.

Adding to 31100213 its reverse (31200113), we get a palindrome (62300326).

It can be divided in two parts, 31100 and 213, that added together give a palindrome (31313).

The spelling of 31100213 in words is "thirty-one million, one hundred thousand, two hundred thirteen".