21567138 has 8 divisors (see below), whose sum is σ = 43134288. Its totient is φ = 7189044.

The previous prime is 21567137. The next prime is 21567151. The reversal of 21567138 is 83176512.

It is a sphenic number, since it is the product of 3 distinct primes.

21567138 is an admirable number.

It is a super-2 number, since 2×21567138² = 930282883022088, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21567099 and 21567108.

It is not an unprimeable number, because it can be changed into a prime (21567137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1797256 + ... + 1797267.

It is an arithmetic number, because the mean of its divisors is an integer number (5391786).

Almost surely, 2^21567138 is an apocalyptic number.

21567138 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21567138 is a wasteful number, since it uses less digits than its factorization.

21567138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3594528.

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

The square root of 21567138 is about 4644.0432814521. The cubic root of 21567138 is about 278.3540250990.

The spelling of 21567138 in words is "twenty-one million, five hundred sixty-seven thousand, one hundred thirty-eight".