20511438899 has 4 divisors (see below), whose sum is σ = 23441644464. Its totient is φ = 17581233336.

The previous prime is 20511438869. The next prime is 20511438907. The reversal of 20511438899 is 99883411502.

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 20511438899 - 2³² = 16216471603 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20511438869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1465102772 + ... + 1465102785.

It is an arithmetic number, because the mean of its divisors is an integer number (5860411116).

Almost surely, 2^20511438899 is an apocalyptic number.

20511438899 is a deficient number, since it is larger than the sum of its proper divisors (2930205565).

20511438899 is an equidigital number, since it uses as much as digits as its factorization.

20511438899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2930205564.

The product of its (nonzero) digits is 622080, while the sum is 50.

The spelling of 20511438899 in words is "twenty billion, five hundred eleven million, four hundred thirty-eight thousand, eight hundred ninety-nine".