21379587 has 8 divisors (see below), whose sum is σ = 28768080. Its totient is φ = 14122080.

The previous prime is 21379571. The next prime is 21379609. The reversal of 21379587 is 78597312.

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

It is not a de Polignac number, because 21379587 - 2⁴ = 21379571 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21379517) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32364 + ... + 33017.

It is an arithmetic number, because the mean of its divisors is an integer number (3596010).

Almost surely, 2^21379587 is an apocalyptic number.

21379587 is a deficient number, since it is larger than the sum of its proper divisors (7388493).

21379587 is a wasteful number, since it uses less digits than its factorization.

21379587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65493.

The product of its digits is 105840, while the sum is 42.

The square root of 21379587 is about 4623.8065487215. The cubic root of 21379587 is about 277.5448056862.

It can be divided in two parts, 213 and 79587, that added together give a triangular number (79800 = T₃₉₉).

The spelling of 21379587 in words is "twenty-one million, three hundred seventy-nine thousand, five hundred eighty-seven".