13561135423666 has 4 divisors (see below), whose sum is σ = 20341703135502. Its totient is φ = 6780567711832.

The previous prime is 13561135423643. The next prime is 13561135423669. The reversal of 13561135423666 is 66632453116531.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12074269788025 + 1486865635641 = 3474805^2 + 1219371^2 .

It is not an unprimeable number, because it can be changed into a prime (13561135423669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3390283855915 + ... + 3390283855918.

Almost surely, 2^{13561135423666} is an apocalyptic number.

13561135423666 is a deficient number, since it is larger than the sum of its proper divisors (6780567711836).

13561135423666 is an equidigital number, since it uses as much as digits as its factorization.

13561135423666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6780567711835.

The product of its digits is 6998400, while the sum is 52.

The spelling of 13561135423666 in words is "thirteen trillion, five hundred sixty-one billion, one hundred thirty-five million, four hundred twenty-three thousand, six hundred sixty-six".