31947421 has 4 divisors (see below), whose sum is σ = 34851744. Its totient is φ = 29043100.

The previous prime is 31947401. The next prime is 31947427. The reversal of 31947421 is 12474913.

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 31947421 - 2⁹ = 31946909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31947427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1452145 + ... + 1452166.

It is an arithmetic number, because the mean of its divisors is an integer number (8712936).

Almost surely, 2^31947421 is an apocalyptic number.

It is an amenable number.

31947421 is a deficient number, since it is larger than the sum of its proper divisors (2904323).

31947421 is a wasteful number, since it uses less digits than its factorization.

31947421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2904322.

The product of its digits is 6048, while the sum is 31.

The square root of 31947421 is about 5652.2049679749. The cubic root of 31947421 is about 317.3062318213.

The spelling of 31947421 in words is "thirty-one million, nine hundred forty-seven thousand, four hundred twenty-one".