11921800969 has 27 divisors (see below), whose sum is σ = 13326444117. Its totient is φ = 10660145184.

The previous prime is 11921800951. The next prime is 11921800981. The reversal of 11921800969 is 96900812911.

The square root of 11921800969 is 109187.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 49519369 + 11872281600 = 7037^2 + 108960^2 .

It is not a de Polignac number, because 11921800969 - 2¹³ = 11921792777 is a prime.

It is a super-2 number, since 2×11921800969² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11921800939) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 52518834 + ... + 52519060.

Almost surely, 2^11921800969 is an apocalyptic number.

11921800969 is the 109187-th square number.

11921800969 is the 54594-th centered octagonal number.

It is an amenable number.

11921800969 is a deficient number, since it is larger than the sum of its proper divisors (1404643148).

11921800969 is an frugal number, since it uses more digits than its factorization.

11921800969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554 (or 277 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 46.

The spelling of 11921800969 in words is "eleven billion, nine hundred twenty-one million, eight hundred thousand, nine hundred sixty-nine".