21384471 has 8 divisors (see below), whose sum is σ = 28534000. Its totient is φ = 14245632.

The previous prime is 21384449. The next prime is 21384479. The reversal of 21384471 is 17448312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21384471 - 2¹¹ = 21382423 is a prime.

It is a super-3 number, since 3×21384471³ (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 (21384479) 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, 6405 + ... + 9153.

It is an arithmetic number, because the mean of its divisors is an integer number (3566750).

Almost surely, 2^21384471 is an apocalyptic number.

21384471 is a deficient number, since it is larger than the sum of its proper divisors (7149529).

21384471 is a wasteful number, since it uses less digits than its factorization.

21384471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5345.

The product of its digits is 5376, while the sum is 30.

The square root of 21384471 is about 4624.3346548450. The cubic root of 21384471 is about 277.5659383929.

The spelling of 21384471 in words is "twenty-one million, three hundred eighty-four thousand, four hundred seventy-one".