11791570921 has 9 divisors (see below), whose sum is σ = 12769916229. Its totient is φ = 10883223936.

The previous prime is 11791570919. The next prime is 11791570949. The reversal of 11791570921 is 12907519711.

It is a happy number.

The square root of 11791570921 is 108589.

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 602162521 + 11189408400 = 24539^2 + 105780^2 .

It is not a de Polignac number, because 11791570921 - 2¹ = 11791570919 is a prime.

It is a super-2 number, since 2×11791570921² (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 (11791570421) 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, 1407481 + ... + 1415833.

It is an arithmetic number, because the mean of its divisors is an integer number (1418879581).

Almost surely, 2^11791570921 is an apocalyptic number.

11791570921 is the 108589-th square number.

11791570921 is the 54295-th centered octagonal number.

It is an amenable number.

11791570921 is a deficient number, since it is larger than the sum of its proper divisors (978345308).

11791570921 is an frugal number, since it uses more digits than its factorization.

11791570921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16732 (or 8366 counting only the distinct ones).

The product of its (nonzero) digits is 39690, while the sum is 43.

The spelling of 11791570921 in words is "eleven billion, seven hundred ninety-one million, five hundred seventy thousand, nine hundred twenty-one".