21421471 has 4 divisors (see below), whose sum is σ = 21590272. Its totient is φ = 21252672.

The previous prime is 21421453. The next prime is 21421489. The reversal of 21421471 is 17412412.

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

It is an interprime number because it is at equal distance from previous prime (21421453) and next prime (21421489).

It is a cyclic number.

It is not a de Polignac number, because 21421471 - 2¹³ = 21413279 is a prime.

It is a super-3 number, since 3×21421471³ (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 (21421451) 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, 84210 + ... + 84463.

It is an arithmetic number, because the mean of its divisors is an integer number (5397568).

Almost surely, 2^21421471 is an apocalyptic number.

21421471 is a deficient number, since it is larger than the sum of its proper divisors (168801).

21421471 is a wasteful number, since it uses less digits than its factorization.

21421471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168800.

The product of its digits is 448, while the sum is 22.

The square root of 21421471 is about 4628.3335013804. Note that the first 3 decimals coincide. The cubic root of 21421471 is about 277.7259302284.

Adding to 21421471 its reverse (17412412), we get a palindrome (38833883).

The spelling of 21421471 in words is "twenty-one million, four hundred twenty-one thousand, four hundred seventy-one".