20742941809 has 4 divisors (see below), whose sum is σ = 20757358080. Its totient is φ = 20728525540.

The previous prime is 20742941771. The next prime is 20742941899. The reversal of 20742941809 is 90814924702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20742941809 - 2¹¹ = 20742939761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20742941899) 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, 7205977 + ... + 7208854.

It is an arithmetic number, because the mean of its divisors is an integer number (5189339520).

Almost surely, 2^20742941809 is an apocalyptic number.

It is an amenable number.

20742941809 is a deficient number, since it is larger than the sum of its proper divisors (14416271).

20742941809 is a wasteful number, since it uses less digits than its factorization.

20742941809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14416270.

The product of its (nonzero) digits is 290304, while the sum is 46.

The spelling of 20742941809 in words is "twenty billion, seven hundred forty-two million, nine hundred forty-one thousand, eight hundred nine".