21387694 has 8 divisors (see below), whose sum is σ = 32128920. Its totient is φ = 10678056.

The previous prime is 21387661. The next prime is 21387697. The reversal of 21387694 is 49678312.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21387697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6124 + ... + 8959.

It is an arithmetic number, because the mean of its divisors is an integer number (4016115).

Almost surely, 2^21387694 is an apocalyptic number.

21387694 is a deficient number, since it is larger than the sum of its proper divisors (10741226).

21387694 is a wasteful number, since it uses less digits than its factorization.

21387694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15794.

The product of its digits is 72576, while the sum is 40.

The square root of 21387694 is about 4624.6831242800. The cubic root of 21387694 is about 277.5798823133.

The spelling of 21387694 in words is "twenty-one million, three hundred eighty-seven thousand, six hundred ninety-four".