31132221 has 8 divisors (see below), whose sum is σ = 42010080. Its totient is φ = 20504592.

The previous prime is 31132201. The next prime is 31132223. The reversal of 31132221 is 12223113.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31132221 - 2⁷ = 31132093 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31132221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31132223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62266 + ... + 62763.

It is an arithmetic number, because the mean of its divisors is an integer number (5251260).

Almost surely, 2^31132221 is an apocalyptic number.

It is an amenable number.

31132221 is a deficient number, since it is larger than the sum of its proper divisors (10877859).

31132221 is a wasteful number, since it uses less digits than its factorization.

31132221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125115.

The product of its digits is 72, while the sum is 15.

The square root of 31132221 is about 5579.6255250689. The cubic root of 31132221 is about 314.5840516491.

Adding to 31132221 its reverse (12223113), we get a palindrome (43355334).

The spelling of 31132221 in words is "thirty-one million, one hundred thirty-two thousand, two hundred twenty-one".