21238536 has 32 divisors (see below), whose sum is σ = 57924000. Its totient is φ = 6435840.

The previous prime is 21238519. The next prime is 21238543. The reversal of 21238536 is 63583212.

It is a super-2 number, since 2×21238536² = 902150822846592, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39961 + ... + 40488.

It is an arithmetic number, because the mean of its divisors is an integer number (1810125).

Almost surely, 2^21238536 is an apocalyptic number.

It is an amenable number.

21238536 is an abundant number, since it is smaller than the sum of its proper divisors (36685464).

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

21238536 is a wasteful number, since it uses less digits than its factorization.

21238536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80469 (or 80465 counting only the distinct ones).

The product of its digits is 8640, while the sum is 30.

The square root of 21238536 is about 4608.5286155128. The cubic root of 21238536 is about 276.9330947468.

The spelling of 21238536 in words is "twenty-one million, two hundred thirty-eight thousand, five hundred thirty-six".