20561827699 has 16 divisors (see below), whose sum is σ = 23551024896. Its totient is φ = 17585632800.

The previous prime is 20561827687. The next prime is 20561827703. The reversal of 20561827699 is 99672816502.

It is a cyclic number.

It is not a de Polignac number, because 20561827699 - 2¹¹ = 20561825651 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20561827609) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10347184 + ... + 10349170.

It is an arithmetic number, because the mean of its divisors is an integer number (1471939056).

Almost surely, 2^20561827699 is an apocalyptic number.

20561827699 is a deficient number, since it is larger than the sum of its proper divisors (2989197197).

20561827699 is a wasteful number, since it uses less digits than its factorization.

20561827699 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4506.

The product of its (nonzero) digits is 3265920, while the sum is 55.

The spelling of 20561827699 in words is "twenty billion, five hundred sixty-one million, eight hundred twenty-seven thousand, six hundred ninety-nine".