1551346615661 has 2 divisors, whose sum is σ = 1551346615662. Its totient is φ = 1551346615660.

The previous prime is 1551346615657. The next prime is 1551346615667. The reversal of 1551346615661 is 1665166431551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1037535774025 + 513810841636 = 1018595^2 + 716806^2 .

It is a cyclic number.

It is not a de Polignac number, because 1551346615661 - 2² = 1551346615657 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1551346615667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 775673307830 + 775673307831.

It is an arithmetic number, because the mean of its divisors is an integer number (775673307831).

Almost surely, 2^{1551346615661} is an apocalyptic number.

It is an amenable number.

1551346615661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1551346615661 is an equidigital number, since it uses as much as digits as its factorization.

1551346615661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944000, while the sum is 50.

The spelling of 1551346615661 in words is "one trillion, five hundred fifty-one billion, three hundred forty-six million, six hundred fifteen thousand, six hundred sixty-one".