31230021 has 16 divisors (see below), whose sum is σ = 43591680. Its totient is φ = 19850160.

The previous prime is 31229999. The next prime is 31230029. The reversal of 31230021 is 12003213.

It is a happy number.

It is not a de Polignac number, because 31230021 - 2⁷ = 31229893 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31229979 and 31230006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31230029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29776 + ... + 30806.

It is an arithmetic number, because the mean of its divisors is an integer number (2724480).

Almost surely, 2^31230021 is an apocalyptic number.

It is an amenable number.

31230021 is a deficient number, since it is larger than the sum of its proper divisors (12361659).

31230021 is a wasteful number, since it uses less digits than its factorization.

31230021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1496.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 31230021 is about 5588.3826819573. The cubic root of 31230021 is about 314.9131229299.

Adding to 31230021 its reverse (12003213), we get a palindrome (43233234).

The spelling of 31230021 in words is "thirty-one million, two hundred thirty thousand, twenty-one".