31061021 has 4 divisors (see below), whose sum is σ = 31647132. Its totient is φ = 30474912.

The previous prime is 31061003. The next prime is 31061047. The reversal of 31061021 is 12016013.

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 15100996 + 15960025 = 3886^2 + 3995^2 .

It is a cyclic number.

It is not a de Polignac number, because 31061021 - 2⁶ = 31060957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31060987 and 31061005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31061071) 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, 292976 + ... + 293081.

It is an arithmetic number, because the mean of its divisors is an integer number (7911783).

Almost surely, 2^31061021 is an apocalyptic number.

It is an amenable number.

31061021 is a deficient number, since it is larger than the sum of its proper divisors (586111).

31061021 is an equidigital number, since it uses as much as digits as its factorization.

31061021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586110.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 31061021 is about 5573.2415163888. The cubic root of 31061021 is about 314.3440486269.

Adding to 31061021 its reverse (12016013), we get a palindrome (43077034).

The spelling of 31061021 in words is "thirty-one million, sixty-one thousand, twenty-one".