21328436 has 12 divisors (see below), whose sum is σ = 37360260. Its totient is φ = 10654080.

The previous prime is 21328423. The next prime is 21328451. The reversal of 21328436 is 63482312.

It can be written as a sum of positive squares in 2 ways, for example, as 12208036 + 9120400 = 3494^2 + 3020^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21328399 and 21328408.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4166 + ... + 7746.

It is an arithmetic number, because the mean of its divisors is an integer number (3113355).

Almost surely, 2^21328436 is an apocalyptic number.

It is an amenable number.

21328436 is a deficient number, since it is larger than the sum of its proper divisors (16031824).

21328436 is a wasteful number, since it uses less digits than its factorization.

21328436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5074 (or 5072 counting only the distinct ones).

The product of its digits is 6912, while the sum is 29.

The square root of 21328436 is about 4618.2719712031. The cubic root of 21328436 is about 277.3232854831.

The spelling of 21328436 in words is "twenty-one million, three hundred twenty-eight thousand, four hundred thirty-six".