21316031 has 8 divisors (see below), whose sum is σ = 23331024. Its totient is φ = 19313920.

The previous prime is 21316027. The next prime is 21316037. The reversal of 21316031 is 13061312.

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 21316031 - 2² = 21316027 is a prime.

It is a super-2 number, since 2×21316031² = 908746355185922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21316037) 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, 431 + ... + 6543.

It is an arithmetic number, because the mean of its divisors is an integer number (2916378).

Almost surely, 2^21316031 is an apocalyptic number.

21316031 is a deficient number, since it is larger than the sum of its proper divisors (2014993).

21316031 is a wasteful number, since it uses less digits than its factorization.

21316031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6441.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 21316031 is about 4616.9287410572. The cubic root of 21316031 is about 277.2695096611.

Adding to 21316031 its reverse (13061312), we get a palindrome (34377343).

The spelling of 21316031 in words is "twenty-one million, three hundred sixteen thousand, thirty-one".