21117711 has 8 divisors (see below), whose sum is σ = 28756224. Its totient is φ = 13778840.

The previous prime is 21117709. The next prime is 21117737. The reversal of 21117711 is 11771112.

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 21117711 - 2¹ = 21117709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21117751) 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, 74745 + ... + 75026.

It is an arithmetic number, because the mean of its divisors is an integer number (3594528).

Almost surely, 2^21117711 is an apocalyptic number.

21117711 is a deficient number, since it is larger than the sum of its proper divisors (7638513).

21117711 is a wasteful number, since it uses less digits than its factorization.

21117711 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149821.

The product of its digits is 98, while the sum is 21.

The square root of 21117711 is about 4595.4010706357. The cubic root of 21117711 is about 276.4069427546.

Adding to 21117711 its reverse (11771112), we get a palindrome (32888823).

The spelling of 21117711 in words is "twenty-one million, one hundred seventeen thousand, seven hundred eleven".