21713887 has 8 divisors (see below), whose sum is σ = 23955120. Its totient is φ = 19554240.

The previous prime is 21713873. The next prime is 21713893. The reversal of 21713887 is 78831712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21713887 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 (21713807) 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, 19837 + ... + 20902.

It is an arithmetic number, because the mean of its divisors is an integer number (2994390).

Almost surely, 2^21713887 is an apocalyptic number.

21713887 is a deficient number, since it is larger than the sum of its proper divisors (2241233).

21713887 is a wasteful number, since it uses less digits than its factorization.

21713887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40793.

The product of its digits is 18816, while the sum is 37.

The square root of 21713887 is about 4659.8161980919. The cubic root of 21713887 is about 278.9839321348.

The spelling of 21713887 in words is "twenty-one million, seven hundred thirteen thousand, eight hundred eighty-seven".