21711471 has 16 divisors (see below), whose sum is σ = 31799040. Its totient is φ = 13115520.

The previous prime is 21711467. The next prime is 21711479. The reversal of 21711471 is 17411712.

It is not a de Polignac number, because 21711471 - 2² = 21711467 is a prime.

It is a super-3 number, since 3×21711471³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21711479) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6970 + ... + 9591.

It is an arithmetic number, because the mean of its divisors is an integer number (1987440).

Almost surely, 2^21711471 is an apocalyptic number.

21711471 is a deficient number, since it is larger than the sum of its proper divisors (10087569).

21711471 is a wasteful number, since it uses less digits than its factorization.

21711471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16606.

The product of its digits is 392, while the sum is 24.

The square root of 21711471 is about 4659.5569531877. The cubic root of 21711471 is about 278.9735846832.

The spelling of 21711471 in words is "twenty-one million, seven hundred eleven thousand, four hundred seventy-one".