1551501605666 has 8 divisors (see below), whose sum is σ = 2327257709904. Its totient is φ = 775749035700.

The previous prime is 1551501605651. The next prime is 1551501605671. The reversal of 1551501605666 is 6665061051551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1551501605666.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1149641 + ... + 2103491.

It is an arithmetic number, because the mean of its divisors is an integer number (290907213738).

Almost surely, 2^{1551501605666} is an apocalyptic number.

1551501605666 is a deficient number, since it is larger than the sum of its proper divisors (775756104238).

1551501605666 is an equidigital number, since it uses as much as digits as its factorization.

1551501605666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1767136.

The product of its (nonzero) digits is 810000, while the sum is 47.

The spelling of 1551501605666 in words is "one trillion, five hundred fifty-one billion, five hundred one million, six hundred five thousand, six hundred sixty-six".