21416993991 has 12 divisors (see below), whose sum is σ = 31120903632. Its totient is φ = 14192498016.

The previous prime is 21416993989. The next prime is 21416994023. The reversal of 21416993991 is 19939961412.

It is a happy number.

21416993991 is a `hidden beast` number, since 21 + 416 + 99 + 39 + 91 = 666.

It is not a de Polignac number, because 21416993991 - 2¹ = 21416993989 is a prime.

It is a super-2 number, since 2×21416993991² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21416993891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7123246 + ... + 7126251.

It is an arithmetic number, because the mean of its divisors is an integer number (2593408636).

Almost surely, 2^21416993991 is an apocalyptic number.

21416993991 is a deficient number, since it is larger than the sum of its proper divisors (9703909641).

21416993991 is a wasteful number, since it uses less digits than its factorization.

21416993991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14249670 (or 14249667 counting only the distinct ones).

The product of its digits is 944784, while the sum is 54.

The spelling of 21416993991 in words is "twenty-one billion, four hundred sixteen million, nine hundred ninety-three thousand, nine hundred ninety-one".