31361921 has 8 divisors (see below), whose sum is σ = 32266080. Its totient is φ = 30465792.

The previous prime is 31361917. The next prime is 31361933. The reversal of 31361921 is 12916313.

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

It is a cyclic number.

It is not a de Polignac number, because 31361921 - 2² = 31361917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31361971) 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, 6410 + ... + 10188.

It is an arithmetic number, because the mean of its divisors is an integer number (4033260).

Almost surely, 2^31361921 is an apocalyptic number.

It is an amenable number.

31361921 is a deficient number, since it is larger than the sum of its proper divisors (904159).

31361921 is a wasteful number, since it uses less digits than its factorization.

31361921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4015.

The product of its digits is 972, while the sum is 26.

The square root of 31361921 is about 5600.1715152306. The cubic root of 31361921 is about 315.3558454468.

The spelling of 31361921 in words is "thirty-one million, three hundred sixty-one thousand, nine hundred twenty-one".