31471021 has 4 divisors (see below), whose sum is σ = 31508352. Its totient is φ = 31433692.

The previous prime is 31471007. The next prime is 31471031. The reversal of 31471021 is 12017413.

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 a de Polignac number, because none of the positive numbers 2^k-31471021 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31471021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31471001) 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, 17371 + ... + 19096.

It is an arithmetic number, because the mean of its divisors is an integer number (7877088).

Almost surely, 2^31471021 is an apocalyptic number.

It is an amenable number.

31471021 is a deficient number, since it is larger than the sum of its proper divisors (37331).

31471021 is an equidigital number, since it uses as much as digits as its factorization.

31471021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37330.

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 31471021 is about 5609.9038316178. The cubic root of 31471021 is about 315.7211026636.

Adding to 31471021 its reverse (12017413), we get a palindrome (43488434).

The spelling of 31471021 in words is "thirty-one million, four hundred seventy-one thousand, twenty-one".