5201556666661 has 4 divisors (see below), whose sum is σ = 5201629206732. Its totient is φ = 5201484126592.

The previous prime is 5201556666641. The next prime is 5201556666671. The reversal of 5201556666661 is 1666666551025.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3234354061761 + 1967202604900 = 1798431^2 + 1402570^2 .

It is a cyclic number.

It is not a de Polignac number, because 5201556666661 - 2²¹ = 5201554569509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5201556666641) 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, 36162370 + ... + 36305923.

It is an arithmetic number, because the mean of its divisors is an integer number (1300407301683).

Almost surely, 2^{5201556666661} is an apocalyptic number.

It is an amenable number.

5201556666661 is a deficient number, since it is larger than the sum of its proper divisors (72540071).

5201556666661 is an equidigital number, since it uses as much as digits as its factorization.

5201556666661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72540070.

The product of its (nonzero) digits is 11664000, while the sum is 55.

The spelling of 5201556666661 in words is "five trillion, two hundred one billion, five hundred fifty-six million, six hundred sixty-six thousand, six hundred sixty-one".