21071471 has 4 divisors (see below), whose sum is σ = 21121944. Its totient is φ = 21021000.

The previous prime is 21071467. The next prime is 21071489. The reversal of 21071471 is 17417012.

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 21071471 - 2² = 21071467 is a prime.

It is a super-3 number, since 3×21071471³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24605 + ... + 25446.

It is an arithmetic number, because the mean of its divisors is an integer number (5280486).

Almost surely, 2^21071471 is an apocalyptic number.

21071471 is a deficient number, since it is larger than the sum of its proper divisors (50473).

21071471 is an equidigital number, since it uses as much as digits as its factorization.

21071471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50472.

The product of its (nonzero) digits is 392, while the sum is 23.

The square root of 21071471 is about 4590.3671966412. The cubic root of 21071471 is about 276.2050522341.

Adding to 21071471 its reverse (17417012), we get a palindrome (38488483).

The spelling of 21071471 in words is "twenty-one million, seventy-one thousand, four hundred seventy-one".