21516757667 has 8 divisors (see below), whose sum is σ = 22811140992. Its totient is φ = 20259892800.

The previous prime is 21516757649. The next prime is 21516757681. The reversal of 21516757667 is 76675761512.

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 21516757667 - 2¹⁴ = 21516741283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21516757607) 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, 9378434 + ... + 9380727.

It is an arithmetic number, because the mean of its divisors is an integer number (2851392624).

Almost surely, 2^21516757667 is an apocalyptic number.

21516757667 is a deficient number, since it is larger than the sum of its proper divisors (1294383325).

21516757667 is a wasteful number, since it uses less digits than its factorization.

21516757667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18759229.

The product of its digits is 3704400, while the sum is 53.

The spelling of 21516757667 in words is "twenty-one billion, five hundred sixteen million, seven hundred fifty-seven thousand, six hundred sixty-seven".