21693138 has 8 divisors (see below), whose sum is σ = 43386288. Its totient is φ = 7231044.

The previous prime is 21693109. The next prime is 21693143. The reversal of 21693138 is 83139612.

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

21693138 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21693099 and 21693108.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1807756 + ... + 1807767.

It is an arithmetic number, because the mean of its divisors is an integer number (5423286).

Almost surely, 2^21693138 is an apocalyptic number.

21693138 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.

21693138 is a wasteful number, since it uses less digits than its factorization.

21693138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3615528.

The product of its digits is 7776, while the sum is 33.

The square root of 21693138 is about 4657.5892906095. The cubic root of 21693138 is about 278.8950415185.

The spelling of 21693138 in words is "twenty-one million, six hundred ninety-three thousand, one hundred thirty-eight".