181687008790621 has 2 divisors, whose sum is σ = 181687008790622. Its totient is φ = 181687008790620.

The previous prime is 181687008790433. The next prime is 181687008790667. The reversal of 181687008790621 is 126097800786181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151750123316100 + 29936885474521 = 12318690^2 + 5471461^2 .

It is a cyclic number.

It is not a de Polignac number, because 181687008790621 - 2¹³ = 181687008782429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181687009790621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90843504395310 + 90843504395311.

It is an arithmetic number, because the mean of its divisors is an integer number (90843504395311).

Almost surely, 2^{181687008790621} is an apocalyptic number.

It is an amenable number.

181687008790621 is a deficient number, since it is larger than the sum of its proper divisors (1).

181687008790621 is an equidigital number, since it uses as much as digits as its factorization.

181687008790621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16257024, while the sum is 64.

The spelling of 181687008790621 in words is "one hundred eighty-one trillion, six hundred eighty-seven billion, eight million, seven hundred ninety thousand, six hundred twenty-one".