21680543727 has 8 divisors (see below), whose sum is σ = 32119324080. Its totient is φ = 14453695800.

The previous prime is 21680543723. The next prime is 21680543767. The reversal of 21680543727 is 72734508612.

21680543727 is a `hidden beast` number, since 2 + 1 + 6 + 80 + 543 + 7 + 27 = 666.

It is not a de Polignac number, because 21680543727 - 2² = 21680543723 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680543723) 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 7 ways as a sum of consecutive naturals, for example, 401491524 + ... + 401491577.

It is an arithmetic number, because the mean of its divisors is an integer number (4014915510).

Almost surely, 2^21680543727 is an apocalyptic number.

21680543727 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21680543727 is a deficient number, since it is larger than the sum of its proper divisors (10438780353).

21680543727 is an equidigital number, since it uses as much as digits as its factorization.

21680543727 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 802983110 (or 802983104 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 45.

The spelling of 21680543727 in words is "twenty-one billion, six hundred eighty million, five hundred forty-three thousand, seven hundred twenty-seven".