31821130 has 16 divisors (see below), whose sum is σ = 62485344. Its totient is φ = 11571280.

The previous prime is 31821113. The next prime is 31821151. The reversal of 31821130 is 3112813.

It is a junction number, because it is equal to n+sod(n) for n = 31821098 and 31821107.

It is an unprimeable number.

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, 144532 + ... + 144751.

It is an arithmetic number, because the mean of its divisors is an integer number (3905334).

Almost surely, 2^31821130 is an apocalyptic number.

31821130 is a deficient number, since it is larger than the sum of its proper divisors (30664214).

31821130 is a wasteful number, since it uses less digits than its factorization.

31821130 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289301.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 31821130 is about 5641.0220705117. The cubic root of 31821130 is about 316.8875663987.

Adding to 31821130 its reverse (3112813), we get a palindrome (34933943).

The spelling of 31821130 in words is "thirty-one million, eight hundred twenty-one thousand, one hundred thirty".