31521121 has 4 divisors (see below), whose sum is σ = 31540912. Its totient is φ = 31501332.

The previous prime is 31521053. The next prime is 31521131. The reversal of 31521121 is 12112513.

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 31521121 - 2¹¹ = 31519073 is a prime.

It is a deceptive number, since it divides R_31521120.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31521095 and 31521104.

It is not an unprimeable number, because it can be changed into a prime (31521131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7275 + ... + 10768.

It is an arithmetic number, because the mean of its divisors is an integer number (7885228).

Almost surely, 2^31521121 is an apocalyptic number.

It is an amenable number.

31521121 is a deficient number, since it is larger than the sum of its proper divisors (19791).

31521121 is a wasteful number, since it uses less digits than its factorization.

31521121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19790.

The product of its digits is 60, while the sum is 16.

The square root of 31521121 is about 5614.3673730884. The cubic root of 31521121 is about 315.8885502665. Note that the first 3 decimals are identical.

Adding to 31521121 its reverse (12112513), we get a palindrome (43633634).

The spelling of 31521121 in words is "thirty-one million, five hundred twenty-one thousand, one hundred twenty-one".