21538934 has 4 divisors (see below), whose sum is σ = 32308404. Its totient is φ = 10769466.

The previous prime is 21538903. The next prime is 21538939. The reversal of 21538934 is 43983512.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 21538894 and 21538903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21538939) by changing a digit.

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 as a sum of consecutive naturals, namely, 5384732 + ... + 5384735.

It is an arithmetic number, because the mean of its divisors is an integer number (8077101).

Almost surely, 2^21538934 is an apocalyptic number.

21538934 is a deficient number, since it is larger than the sum of its proper divisors (10769470).

21538934 is a wasteful number, since it uses less digits than its factorization.

21538934 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10769469.

The product of its digits is 25920, while the sum is 35.

The square root of 21538934 is about 4641.0057099728. The cubic root of 21538934 is about 278.2326348368.

The spelling of 21538934 in words is "twenty-one million, five hundred thirty-eight thousand, nine hundred thirty-four".