21085713 has 12 divisors (see below), whose sum is σ = 33226128. Its totient is φ = 12779160.

The previous prime is 21085709. The next prime is 21085717. The reversal of 21085713 is 31758012.

It is an interprime number because it is at equal distance from previous prime (21085709) and next prime (21085717).

It is not a de Polignac number, because 21085713 - 2² = 21085709 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21085717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 106395 + ... + 106592.

It is an arithmetic number, because the mean of its divisors is an integer number (2768844).

Almost surely, 2^21085713 is an apocalyptic number.

It is an amenable number.

21085713 is a deficient number, since it is larger than the sum of its proper divisors (12140415).

21085713 is a wasteful number, since it uses less digits than its factorization.

21085713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213004 (or 213001 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 21085713 is about 4591.9182266238. The cubic root of 21085713 is about 276.2672663123.

The spelling of 21085713 in words is "twenty-one million, eighty-five thousand, seven hundred thirteen".