11811736821 has 16 divisors (see below), whose sum is σ = 16677158400. Its totient is φ = 7415367408.

The previous prime is 11811736819. The next prime is 11811736831. The reversal of 11811736821 is 12863711811.

It is not a de Polignac number, because 11811736821 - 2¹ = 11811736819 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 11811736821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11811736831) 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, 610911 + ... + 629948.

It is an arithmetic number, because the mean of its divisors is an integer number (1042322400).

Almost surely, 2^11811736821 is an apocalyptic number.

It is an amenable number.

11811736821 is a deficient number, since it is larger than the sum of its proper divisors (4865421579).

11811736821 is a wasteful number, since it uses less digits than its factorization.

11811736821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1241048.

The product of its digits is 16128, while the sum is 39.

The spelling of 11811736821 in words is "eleven billion, eight hundred eleven million, seven hundred thirty-six thousand, eight hundred twenty-one".