21387104 has 12 divisors (see below), whose sum is σ = 42105924. Its totient is φ = 10693536.

The previous prime is 21387101. The next prime is 21387109. The reversal of 21387104 is 40178312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21387101) 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, 334142 + ... + 334205.

It is an arithmetic number, because the mean of its divisors is an integer number (3508827).

Almost surely, 2^21387104 is an apocalyptic number.

It is an amenable number.

21387104 is a deficient number, since it is larger than the sum of its proper divisors (20718820).

21387104 is an equidigital number, since it uses as much as digits as its factorization.

21387104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 668357 (or 668349 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 21387104 is about 4624.6193356859. The cubic root of 21387104 is about 277.5773298542.

The spelling of 21387104 in words is "twenty-one million, three hundred eighty-seven thousand, one hundred four".