21516994873 has 8 divisors (see below), whose sum is σ = 24045600096. Its totient is φ = 19083808800.

The previous prime is 21516994871. The next prime is 21516994901. The reversal of 21516994873 is 37849961512.

It is a happy number.

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 21516994873 - 2¹ = 21516994871 is a prime.

It is a super-2 number, since 2×21516994873² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21516994871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23854311 + ... + 23855212.

It is an arithmetic number, because the mean of its divisors is an integer number (3005700012).

Almost surely, 2^21516994873 is an apocalyptic number.

It is an amenable number.

21516994873 is a deficient number, since it is larger than the sum of its proper divisors (2528605223).

21516994873 is a wasteful number, since it uses less digits than its factorization.

21516994873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47709575.

The product of its digits is 3265920, while the sum is 55.

The spelling of 21516994873 in words is "twenty-one billion, five hundred sixteen million, nine hundred ninety-four thousand, eight hundred seventy-three".