31143521 has 2 divisors, whose sum is σ = 31143522. Its totient is φ = 31143520.

The previous prime is 31143493. The next prime is 31143551. The reversal of 31143521 is 12534113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29855296 + 1288225 = 5464^2 + 1135^2 .

It is a cyclic number.

It is not a de Polignac number, because 31143521 - 2¹⁰ = 31142497 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 31143493 and 31143502.

It is not a weakly prime, because it can be changed into another prime (31143551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15571760 + 15571761.

It is an arithmetic number, because the mean of its divisors is an integer number (15571761).

Almost surely, 2^31143521 is an apocalyptic number.

It is an amenable number.

31143521 is a deficient number, since it is larger than the sum of its proper divisors (1).

31143521 is an equidigital number, since it uses as much as digits as its factorization.

31143521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 360, while the sum is 20.

The square root of 31143521 is about 5580.6380459585. The cubic root of 31143521 is about 314.6221083597.

Adding to 31143521 its reverse (12534113), we get a palindrome (43677634).

The spelling of 31143521 in words is "thirty-one million, one hundred forty-three thousand, five hundred twenty-one".