11657978449 has 8 divisors (see below), whose sum is σ = 12629036840. Its totient is φ = 10761208848.

The previous prime is 11657978407. The next prime is 11657978483. The reversal of 11657978449 is 94487975611.

It can be written as a sum of positive squares in 4 ways, for example, as 7433888400 + 4224090049 = 86220^2 + 64993^2 .

It is not a de Polignac number, because 11657978449 - 2²⁹ = 11121107537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11657978249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2650962 + ... + 2655355.

It is an arithmetic number, because the mean of its divisors is an integer number (1578629605).

Almost surely, 2^11657978449 is an apocalyptic number.

It is an amenable number.

11657978449 is a deficient number, since it is larger than the sum of its proper divisors (971058391).

11657978449 is an frugal number, since it uses more digits than its factorization.

11657978449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5306356 (or 5306330 counting only the distinct ones).

The product of its digits is 15240960, while the sum is 61.

The spelling of 11657978449 in words is "eleven billion, six hundred fifty-seven million, nine hundred seventy-eight thousand, four hundred forty-nine".