21456471 has 16 divisors (see below), whose sum is σ = 29272320. Its totient is φ = 13975680.

The previous prime is 21456469. The next prime is 21456481. The reversal of 21456471 is 17465412.

It is not a de Polignac number, because 21456471 - 2¹ = 21456469 is a prime.

It is a super-3 number, since 3×21456471³ (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 (21456481) 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, 42406 + ... + 42908.

It is an arithmetic number, because the mean of its divisors is an integer number (1829520).

Almost surely, 2^21456471 is an apocalyptic number.

21456471 is a deficient number, since it is larger than the sum of its proper divisors (7815849).

21456471 is a wasteful number, since it uses less digits than its factorization.

21456471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 806.

The product of its digits is 6720, while the sum is 30.

The square root of 21456471 is about 4632.1130167560. The cubic root of 21456471 is about 277.8771043842.

The spelling of 21456471 in words is "twenty-one million, four hundred fifty-six thousand, four hundred seventy-one".