21377842705 has 4 divisors (see below), whose sum is σ = 25653411252. Its totient is φ = 17102274160.

The previous prime is 21377842697. The next prime is 21377842711. The reversal of 21377842705 is 50724877312.

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 12024438336 + 9353404369 = 109656^2 + 96713^2 .

It is not a de Polignac number, because 21377842705 - 2³ = 21377842697 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2137784266 + ... + 2137784275.

It is an arithmetic number, because the mean of its divisors is an integer number (6413352813).

Almost surely, 2^21377842705 is an apocalyptic number.

It is an amenable number.

21377842705 is a deficient number, since it is larger than the sum of its proper divisors (4275568547).

21377842705 is an equidigital number, since it uses as much as digits as its factorization.

21377842705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4275568546.

The product of its (nonzero) digits is 658560, while the sum is 46.

The spelling of 21377842705 in words is "twenty-one billion, three hundred seventy-seven million, eight hundred forty-two thousand, seven hundred five".