21424536 has 48 divisors (see below), whose sum is σ = 66315600. Its totient is φ = 6121152.

The previous prime is 21424511. The next prime is 21424547. The reversal of 21424536 is 63542412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20751 + ... + 21758.

It is an arithmetic number, because the mean of its divisors is an integer number (1381575).

Almost surely, 2^21424536 is an apocalyptic number.

It is an amenable number.

21424536 is an abundant number, since it is smaller than the sum of its proper divisors (44891064).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21424536 is a wasteful number, since it uses less digits than its factorization.

21424536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42528 (or 42521 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 21424536 is about 4628.6646022368. The cubic root of 21424536 is about 277.7391753409.

Adding to 21424536 its reverse (63542412), we get a palindrome (84966948).

The spelling of 21424536 in words is "twenty-one million, four hundred twenty-four thousand, five hundred thirty-six".