31420421 has 4 divisors (see below), whose sum is σ = 31454892. Its totient is φ = 31385952.

The previous prime is 31420409. The next prime is 31420447. The reversal of 31420421 is 12402413.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12402413 = 349 ⋅35537.

It can be written as a sum of positive squares in 2 ways, for example, as 11937025 + 19483396 = 3455^2 + 4414^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31420421 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 31420421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31420621) 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, 15830 + ... + 17703.

It is an arithmetic number, because the mean of its divisors is an integer number (7863723).

Almost surely, 2^31420421 is an apocalyptic number.

It is an amenable number.

31420421 is a deficient number, since it is larger than the sum of its proper divisors (34471).

31420421 is an equidigital number, since it uses as much as digits as its factorization.

31420421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34470.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 31420421 is about 5605.3921361489. The cubic root of 31420421 is about 315.5518034491.

Adding to 31420421 its reverse (12402413), we get a palindrome (43822834).

The spelling of 31420421 in words is "thirty-one million, four hundred twenty thousand, four hundred twenty-one".