1188815521 has 2 divisors, whose sum is σ = 1188815522. Its totient is φ = 1188815520.

The previous prime is 1188815489. The next prime is 1188815527. The reversal of 1188815521 is 1255188811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 636048400 + 552767121 = 25220^2 + 23511^2 .

It is a cyclic number.

It is not a de Polignac number, because 1188815521 - 2⁵ = 1188815489 is a prime.

It is not a weakly prime, because it can be changed into another prime (1188815527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 594407760 + 594407761.

It is an arithmetic number, because the mean of its divisors is an integer number (594407761).

Almost surely, 2^1188815521 is an apocalyptic number.

It is an amenable number.

1188815521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1188815521 is an equidigital number, since it uses as much as digits as its factorization.

1188815521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25600, while the sum is 40.

The square root of 1188815521 is about 34479.2041816513. The cubic root of 1188815521 is about 1059.3467913942.

The spelling of 1188815521 in words is "one billion, one hundred eighty-eight million, eight hundred fifteen thousand, five hundred twenty-one".