21173711 has 4 divisors (see below), whose sum is σ = 22802472. Its totient is φ = 19544952.

The previous prime is 21173701. The next prime is 21173717. The reversal of 21173711 is 11737112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21173711 - 2¹⁸ = 20911567 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 (21173717) 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 3 ways as a sum of consecutive naturals, for example, 814361 + ... + 814386.

It is an arithmetic number, because the mean of its divisors is an integer number (5700618).

Almost surely, 2^21173711 is an apocalyptic number.

21173711 is a deficient number, since it is larger than the sum of its proper divisors (1628761).

21173711 is a wasteful number, since it uses less digits than its factorization.

21173711 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1628760.

The product of its digits is 294, while the sum is 23.

The square root of 21173711 is about 4601.4900847443. The cubic root of 21173711 is about 276.6510526502.

The spelling of 21173711 in words is "twenty-one million, one hundred seventy-three thousand, seven hundred eleven".