11195967721 has 9 divisors (see below), whose sum is σ = 11818365111. Its totient is φ = 10604801664.

The previous prime is 11195967709. The next prime is 11195967743. The reversal of 11195967721 is 12776959111.

It is a happy number.

The square root of 11195967721 is 105811.

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

It can be written as a sum of positive squares in only one way, i.e., 2025990121 + 9169977600 = 45011^2 + 95760^2 .

It is not a de Polignac number, because 11195967721 - 2⁵ = 11195967689 is a prime.

It is a super-3 number, since 3×11195967721³ (a number of 31 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11195967701) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2007625 + ... + 2013193.

It is an arithmetic number, because the mean of its divisors is an integer number (1313151679).

Almost surely, 2^11195967721 is an apocalyptic number.

11195967721 is the 105811-st square number.

11195967721 is the 52906-th centered octagonal number.

It is an amenable number.

11195967721 is a deficient number, since it is larger than the sum of its proper divisors (622397390).

11195967721 is an frugal number, since it uses more digits than its factorization.

11195967721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11176 (or 5588 counting only the distinct ones).

The product of its digits is 238140, while the sum is 49.

Multiplying 11195967721 by its sum of digits (49), we get a square (548602418329 = 740677²).

The spelling of 11195967721 in words is "eleven billion, one hundred ninety-five million, nine hundred sixty-seven thousand, seven hundred twenty-one".