20511234899 has 4 divisors (see below), whose sum is σ = 20658797880. Its totient is φ = 20363671920.

The previous prime is 20511234871. The next prime is 20511234917. The reversal of 20511234899 is 99843211502.

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 20511234899 - 2³² = 16216267603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20511234839) 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, 73781282 + ... + 73781559.

It is an arithmetic number, because the mean of its divisors is an integer number (5164699470).

Almost surely, 2^20511234899 is an apocalyptic number.

20511234899 is a deficient number, since it is larger than the sum of its proper divisors (147562981).

20511234899 is a wasteful number, since it uses less digits than its factorization.

20511234899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147562980.

The product of its (nonzero) digits is 155520, while the sum is 44.

The spelling of 20511234899 in words is "twenty billion, five hundred eleven million, two hundred thirty-four thousand, eight hundred ninety-nine".