21016551587 has 8 divisors (see below), whose sum is σ = 21696263040. Its totient is φ = 20336950080.

The previous prime is 21016551533. The next prime is 21016551593. The reversal of 21016551587 is 78515561012.

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 21016551587 - 2⁸ = 21016551331 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21016551527) 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, 561989 + ... + 598217.

It is an arithmetic number, because the mean of its divisors is an integer number (2712032880).

Almost surely, 2^21016551587 is an apocalyptic number.

21016551587 is a deficient number, since it is larger than the sum of its proper divisors (679711453).

21016551587 is a wasteful number, since it uses less digits than its factorization.

21016551587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54973.

The product of its (nonzero) digits is 84000, while the sum is 41.

The spelling of 21016551587 in words is "twenty-one billion, sixteen million, five hundred fifty-one thousand, five hundred eighty-seven".