1661623150321 has 4 divisors (see below), whose sum is σ = 1661667719652. Its totient is φ = 1661578580992.

The previous prime is 1661623150283. The next prime is 1661623150367. The reversal of 1661623150321 is 1230513261661.

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 1365534810721 + 296088339600 = 1168561^2 + 544140^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661623150321 - 2¹⁹ = 1661622626033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661623150391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22228696 + ... + 22303321.

It is an arithmetic number, because the mean of its divisors is an integer number (415416929913).

Almost surely, 2^{1661623150321} is an apocalyptic number.

It is an amenable number.

1661623150321 is a deficient number, since it is larger than the sum of its proper divisors (44569331).

1661623150321 is an equidigital number, since it uses as much as digits as its factorization.

1661623150321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44569330.

The product of its (nonzero) digits is 38880, while the sum is 37.

The spelling of 1661623150321 in words is "one trillion, six hundred sixty-one billion, six hundred twenty-three million, one hundred fifty thousand, three hundred twenty-one".