21424527 has 16 divisors (see below), whose sum is σ = 32417280. Its totient is φ = 13978296.

The previous prime is 21424511. The next prime is 21424547. The reversal of 21424527 is 72542412.

It is not a de Polignac number, because 21424527 - 2⁴ = 21424511 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21424527.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424547) 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, 7173 + ... + 9710.

It is an arithmetic number, because the mean of its divisors is an integer number (2026080).

Almost surely, 2^21424527 is an apocalyptic number.

21424527 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21424527 is a deficient number, since it is larger than the sum of its proper divisors (10992753).

21424527 is a wasteful number, since it uses less digits than its factorization.

21424527 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16939 (or 16933 counting only the distinct ones).

The product of its digits is 4480, while the sum is 27.

The square root of 21424527 is about 4628.6636300341. The cubic root of 21424527 is about 277.7391364501.

Adding to 21424527 its reverse (72542412), we get a palindrome (93966939).

The spelling of 21424527 in words is "twenty-one million, four hundred twenty-four thousand, five hundred twenty-seven".