21587671 has 8 divisors (see below), whose sum is σ = 26123040. Its totient is φ = 17415168.

The previous prime is 21587659. The next prime is 21587681. The reversal of 21587671 is 17678512.

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

It is a cyclic number.

It is not a de Polignac number, because 21587671 - 2¹³ = 21579479 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21587671.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21587611) 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, 90586 + ... + 90823.

It is an arithmetic number, because the mean of its divisors is an integer number (3265380).

Almost surely, 2^21587671 is an apocalyptic number.

21587671 is a deficient number, since it is larger than the sum of its proper divisors (4535369).

21587671 is a wasteful number, since it uses less digits than its factorization.

21587671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181433.

The product of its digits is 23520, while the sum is 37.

The square root of 21587671 is about 4646.2534369102. The cubic root of 21587671 is about 278.4423327574.

The spelling of 21587671 in words is "twenty-one million, five hundred eighty-seven thousand, six hundred seventy-one".