21083814455761 has 4 divisors (see below), whose sum is σ = 21084122420532. Its totient is φ = 21083506490992.

The previous prime is 21083814455719. The next prime is 21083814455819. The reversal of 21083814455761 is 16755441838012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13298012462736 + 7785801993025 = 3646644^2 + 2790305^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21083814455761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21083814455701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 153879670 + ... + 154016623.

It is an arithmetic number, because the mean of its divisors is an integer number (5271030605133).

Almost surely, 2^{21083814455761} is an apocalyptic number.

It is an amenable number.

21083814455761 is a deficient number, since it is larger than the sum of its proper divisors (307964771).

21083814455761 is an equidigital number, since it uses as much as digits as its factorization.

21083814455761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307964770.

The product of its (nonzero) digits is 6451200, while the sum is 55.

The spelling of 21083814455761 in words is "twenty-one trillion, eighty-three billion, eight hundred fourteen million, four hundred fifty-five thousand, seven hundred sixty-one".