31430521 has 4 divisors (see below), whose sum is σ = 31531252. Its totient is φ = 31329792.

The previous prime is 31430473. The next prime is 31430527. The reversal of 31430521 is 12503413.

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 783225 + 30647296 = 885^2 + 5536^2 .

It is a cyclic number.

It is not a de Polignac number, because 31430521 - 2⁷ = 31430393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31430527) 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, 49896 + ... + 50521.

It is an arithmetic number, because the mean of its divisors is an integer number (7882813).

Almost surely, 2^31430521 is an apocalyptic number.

It is an amenable number.

31430521 is a deficient number, since it is larger than the sum of its proper divisors (100731).

31430521 is a wasteful number, since it uses less digits than its factorization.

31430521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100730.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 31430521 is about 5606.2929819980. The cubic root of 31430521 is about 315.5856108869.

Adding to 31430521 its reverse (12503413), we get a palindrome (43933934).

The spelling of 31430521 in words is "thirty-one million, four hundred thirty thousand, five hundred twenty-one".