15511561606655 has 4 divisors (see below), whose sum is σ = 18613873927992. Its totient is φ = 12409249285320.

The previous prime is 15511561606649. The next prime is 15511561606657. The reversal of 15511561606655 is 55660616511551.

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

It is not a de Polignac number, because 15511561606655 - 2⁶ = 15511561606591 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15511561606597 and 15511561606606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15511561606657) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1551156160661 + ... + 1551156160670.

It is an arithmetic number, because the mean of its divisors is an integer number (4653468481998).

Almost surely, 2^{15511561606655} is an apocalyptic number.

15511561606655 is a deficient number, since it is larger than the sum of its proper divisors (3102312321337).

15511561606655 is an equidigital number, since it uses as much as digits as its factorization.

15511561606655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3102312321336.

The product of its (nonzero) digits is 4050000, while the sum is 53.

The spelling of 15511561606655 in words is "fifteen trillion, five hundred eleven billion, five hundred sixty-one million, six hundred six thousand, six hundred fifty-five".