21516240366 has 96 divisors (see below), whose sum is σ = 49758535008. Its totient is φ = 6696069120.

The previous prime is 21516240359. The next prime is 21516240373. The reversal of 21516240366 is 66304261512.

21516240366 is a `hidden beast` number, since 2 + 1 + 51 + 6 + 240 + 366 = 666.

It is an interprime number because it is at equal distance from previous prime (21516240359) and next prime (21516240373).

It is a self number, because there is not a number n which added to its sum of digits gives 21516240366.

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 26530101 + ... + 26530911.

It is an arithmetic number, because the mean of its divisors is an integer number (518318073).

Almost surely, 2^21516240366 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21516240366, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24879267504).

21516240366 is an abundant number, since it is smaller than the sum of its proper divisors (28242294642).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21516240366 is a wasteful number, since it uses less digits than its factorization.

21516240366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1426 (or 1423 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21516240366 in words is "twenty-one billion, five hundred sixteen million, two hundred forty thousand, three hundred sixty-six".