21316499661600 has 2592 divisors, whose sum is σ = 95224154014080. Its totient is φ = 4421910528000.

The previous prime is 21316499661593. The next prime is 21316499661623. The reversal of 21316499661600 is 616699461312.

It is a happy number.

21316499661600 is a `hidden beast` number, since 2 + 1 + 3 + 16 + 4 + 9 + 9 + 6 + 616 + 0 + 0 = 666.

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 431 ways as a sum of consecutive naturals, for example, 21126361896 + ... + 21126362904.

It is an arithmetic number, because the mean of its divisors is an integer number (36737713740).

Almost surely, 2^{21316499661600} is an apocalyptic number.

21316499661600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21316499661600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47612077007040).

21316499661600 is an abundant number, since it is smaller than the sum of its proper divisors (73907654352480).

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

21316499661600 is a wasteful number, since it uses less digits than its factorization.

21316499661600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1164 (or 1131 counting only the distinct ones).

The product of its (nonzero) digits is 2519424, while the sum is 54.

The spelling of 21316499661600 in words is "twenty-one trillion, three hundred sixteen billion, four hundred ninety-nine million, six hundred sixty-one thousand, six hundred".