31132021 has 4 divisors (see below), whose sum is σ = 31642444. Its totient is φ = 30621600.

The previous prime is 31131979. The next prime is 31132027. The reversal of 31132021 is 12023113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12023113 = 37 ⋅324949.

It can be written as a sum of positive squares in 2 ways, for example, as 8910225 + 22221796 = 2985^2 + 4714^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31132021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31131992 and 31132010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31132027) 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, 255120 + ... + 255241.

It is an arithmetic number, because the mean of its divisors is an integer number (7910611).

Almost surely, 2^31132021 is an apocalyptic number.

It is an amenable number.

31132021 is a deficient number, since it is larger than the sum of its proper divisors (510423).

31132021 is an equidigital number, since it uses as much as digits as its factorization.

31132021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 510422.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 31132021 is about 5579.6076026904. The cubic root of 31132021 is about 314.5833779961.

Adding to 31132021 its reverse (12023113), we get a palindrome (43155134).

The spelling of 31132021 in words is "thirty-one million, one hundred thirty-two thousand, twenty-one".