31678421 has 4 divisors (see below), whose sum is σ = 31723200. Its totient is φ = 31633644.

The previous prime is 31678403. The next prime is 31678433. The reversal of 31678421 is 12487613.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12487613 = 211 ⋅59183.

It is a cyclic number.

It is not a de Polignac number, because 31678421 - 2¹⁸ = 31416277 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 (31678481) 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, 21311 + ... + 22748.

It is an arithmetic number, because the mean of its divisors is an integer number (7930800).

Almost surely, 2^31678421 is an apocalyptic number.

It is an amenable number.

31678421 is a deficient number, since it is larger than the sum of its proper divisors (44779).

31678421 is an equidigital number, since it uses as much as digits as its factorization.

31678421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44778.

The product of its digits is 8064, while the sum is 32.

The square root of 31678421 is about 5628.3586417356. The cubic root of 31678421 is about 316.4131386579.

The spelling of 31678421 in words is "thirty-one million, six hundred seventy-eight thousand, four hundred twenty-one".