1621003550161 has 2 divisors, whose sum is σ = 1621003550162. Its totient is φ = 1621003550160.

The previous prime is 1621003550141. The next prime is 1621003550171. The reversal of 1621003550161 is 1610553001261.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1353255257025 + 267748293136 = 1163295^2 + 517444^2 .

It is an emirp because it is prime and its reverse (1610553001261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1621003550161 - 2³³ = 1612413615569 is a prime.

It is not a weakly prime, because it can be changed into another prime (1621003550141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810501775080 + 810501775081.

It is an arithmetic number, because the mean of its divisors is an integer number (810501775081).

Almost surely, 2^{1621003550161} is an apocalyptic number.

It is an amenable number.

1621003550161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621003550161 is an equidigital number, since it uses as much as digits as its factorization.

1621003550161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 31.

The spelling of 1621003550161 in words is "one trillion, six hundred twenty-one billion, three million, five hundred fifty thousand, one hundred sixty-one".