21051941779 has 4 divisors (see below), whose sum is σ = 22965754680. Its totient is φ = 19138128880.

The previous prime is 21051941777. The next prime is 21051941843. The reversal of 21051941779 is 97714915012.

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

It is a cyclic number.

It is not a de Polignac number, because 21051941779 - 2¹ = 21051941777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21051941773) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 956906434 + ... + 956906455.

It is an arithmetic number, because the mean of its divisors is an integer number (5741438670).

Almost surely, 2^21051941779 is an apocalyptic number.

21051941779 is a deficient number, since it is larger than the sum of its proper divisors (1913812901).

21051941779 is a wasteful number, since it uses less digits than its factorization.

21051941779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1913812900.

The product of its (nonzero) digits is 158760, while the sum is 46.

The spelling of 21051941779 in words is "twenty-one billion, fifty-one million, nine hundred forty-one thousand, seven hundred seventy-nine".