21828471 has 24 divisors (see below), whose sum is σ = 34101504. Its totient is φ = 12383280.

The previous prime is 21828467. The next prime is 21828479. The reversal of 21828471 is 17482812.

It is a happy number.

It is not a de Polignac number, because 21828471 - 2² = 21828467 is a prime.

It is a super-3 number, since 3×21828471³ (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 (21828479) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23506 + ... + 24416.

It is an arithmetic number, because the mean of its divisors is an integer number (1420896).

Almost surely, 2^21828471 is an apocalyptic number.

21828471 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21828471 is a deficient number, since it is larger than the sum of its proper divisors (12273033).

21828471 is a wasteful number, since it uses less digits than its factorization.

21828471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1091 (or 1084 counting only the distinct ones).

The product of its digits is 7168, while the sum is 33.

The square root of 21828471 is about 4672.0949262617. The cubic root of 21828471 is about 279.4738034188.

The spelling of 21828471 in words is "twenty-one million, eight hundred twenty-eight thousand, four hundred seventy-one".