31085521 has 4 divisors (see below), whose sum is σ = 31549552. Its totient is φ = 30621492.

The previous prime is 31085519. The next prime is 31085557. The reversal of 31085521 is 12558013.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31085521 - 2¹ = 31085519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31085321) 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, 231915 + ... + 232048.

It is an arithmetic number, because the mean of its divisors is an integer number (7887388).

Almost surely, 2^31085521 is an apocalyptic number.

It is an amenable number.

31085521 is a deficient number, since it is larger than the sum of its proper divisors (464031).

31085521 is an equidigital number, since it uses as much as digits as its factorization.

31085521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 464030.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 31085521 is about 5575.4390858479. The cubic root of 31085521 is about 314.4266752861.

The spelling of 31085521 in words is "thirty-one million, eighty-five thousand, five hundred twenty-one".