20171650621 has 2 divisors, whose sum is σ = 20171650622. Its totient is φ = 20171650620.

The previous prime is 20171650589. The next prime is 20171650657. The reversal of 20171650621 is 12605617102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15774104025 + 4397546596 = 125595^2 + 66314^2 .

It is a cyclic number.

It is not a de Polignac number, because 20171650621 - 2⁵ = 20171650589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20171650691) 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 as a sum of consecutive naturals, namely, 10085825310 + 10085825311.

It is an arithmetic number, because the mean of its divisors is an integer number (10085825311).

Almost surely, 2^20171650621 is an apocalyptic number.

It is an amenable number.

20171650621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20171650621 is an equidigital number, since it uses as much as digits as its factorization.

20171650621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 31.

The spelling of 20171650621 in words is "twenty billion, one hundred seventy-one million, six hundred fifty thousand, six hundred twenty-one".