31708421 has 8 divisors (see below), whose sum is σ = 33146880. Its totient is φ = 30274992.

The previous prime is 31708393. The next prime is 31708423. The reversal of 31708421 is 12480713.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-31708421 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 (31708423) 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 7 ways as a sum of consecutive naturals, for example, 18236 + ... + 19898.

It is an arithmetic number, because the mean of its divisors is an integer number (4143360).

Almost surely, 2^31708421 is an apocalyptic number.

It is an amenable number.

31708421 is a deficient number, since it is larger than the sum of its proper divisors (1438459).

31708421 is a wasteful number, since it uses less digits than its factorization.

31708421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2515.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 31708421 is about 5631.0230864382. The cubic root of 31708421 is about 316.5129900073.

The spelling of 31708421 in words is "thirty-one million, seven hundred eight thousand, four hundred twenty-one".