21675138 has 16 divisors (see below), whose sum is σ = 44749056. Its totient is φ = 6991920.

The previous prime is 21675133. The next prime is 21675167. The reversal of 21675138 is 83157612.

It is a junction number, because it is equal to n+sod(n) for n = 21675099 and 21675108.

It is not an unprimeable number, because it can be changed into a prime (21675133) 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 in 7 ways as a sum of consecutive naturals, for example, 58081 + ... + 58452.

It is an arithmetic number, because the mean of its divisors is an integer number (2796816).

Almost surely, 2^21675138 is an apocalyptic number.

21675138 is an abundant number, since it is smaller than the sum of its proper divisors (23073918).

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

21675138 is a wasteful number, since it uses less digits than its factorization.

21675138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116569.

The product of its digits is 10080, while the sum is 33.

The square root of 21675138 is about 4655.6565594983. The cubic root of 21675138 is about 278.8178819443.

The spelling of 21675138 in words is "twenty-one million, six hundred seventy-five thousand, one hundred thirty-eight".