21756713 has 8 divisors (see below), whose sum is σ = 23970816. Its totient is φ = 19582000.

The previous prime is 21756677. The next prime is 21756733. The reversal of 21756713 is 31765712.

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 21756713 - 2⁶ = 21756649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21756713.

It is not an unprimeable number, because it can be changed into a prime (21756733) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8681 + ... + 10902.

It is an arithmetic number, because the mean of its divisors is an integer number (2996352).

Almost surely, 2^21756713 is an apocalyptic number.

It is an amenable number.

21756713 is a deficient number, since it is larger than the sum of its proper divisors (2214103).

21756713 is a wasteful number, since it uses less digits than its factorization.

21756713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19695.

The product of its digits is 8820, while the sum is 32.

The square root of 21756713 is about 4664.4091801642. The cubic root of 21756713 is about 279.1672237409.

It can be divided in two parts, 2175 and 6713, that added together give a palindrome (8888).

The spelling of 21756713 in words is "twenty-one million, seven hundred fifty-six thousand, seven hundred thirteen".