135561666969 has 81 divisors (see below), whose sum is σ = 209909363391. Its totient is φ = 84300095520.

The previous prime is 135561666943. The next prime is 135561666997. The reversal of 135561666969 is 969666165531.

The square root of 135561666969 is 368187.

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., 121302441225 + 14259225744 = 348285^2 + 119412^2 .

It is not a de Polignac number, because 135561666969 - 2⁷ = 135561666841 is a prime.

It is a super-2 number, since 2×135561666969² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (135561662969) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 1266931414 + ... + 1266931520.

Almost surely, 2^135561666969 is an apocalyptic number.

135561666969 is the 368187-th square number.

135561666969 is the 184094-th centered octagonal number.

It is an amenable number.

135561666969 is a deficient number, since it is larger than the sum of its proper divisors (74347696422).

135561666969 is an equidigital number, since it uses as much as digits as its factorization.

135561666969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356 (or 178 counting only the distinct ones).

The product of its digits is 47239200, while the sum is 63.

The spelling of 135561666969 in words is "one hundred thirty-five billion, five hundred sixty-one million, six hundred sixty-six thousand, nine hundred sixty-nine".