31380100 has 36 divisors (see below), whose sum is σ = 68722164. Its totient is φ = 12436480.

The previous prime is 31380031. The next prime is 31380101. The reversal of 31380100 is 108313.

It can be written as a sum of positive squares in 6 ways, for example, as 11737476 + 19642624 = 3426^2 + 4432^2 .

It is not an unprimeable number, because it can be changed into a prime (31380101) 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 11 ways as a sum of consecutive naturals, for example, 9912 + ... + 12688.

It is an arithmetic number, because the mean of its divisors is an integer number (1908949).

Almost surely, 2^31380100 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31380100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34361082).

31380100 is an abundant number, since it is smaller than the sum of its proper divisors (37342064).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31380100 is a wasteful number, since it uses less digits than its factorization.

31380100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2904 (or 2897 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 31380100 is about 5601.7943553829. The cubic root of 31380100 is about 315.4167658922.

Adding to 31380100 its reverse (108313), we get a palindrome (31488413).

The spelling of 31380100 in words is "thirty-one million, three hundred eighty thousand, one hundred".