201550021 has 2 divisors, whose sum is σ = 201550022. Its totient is φ = 201550020.

The previous prime is 201550009. The next prime is 201550031. The reversal of 201550021 is 120055102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 194184225 + 7365796 = 13935^2 + 2714^2 .

It is a cyclic number.

It is not a de Polignac number, because 201550021 - 2²³ = 193161413 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 201549977 and 201550004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201550001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100775010 + 100775011.

It is an arithmetic number, because the mean of its divisors is an integer number (100775011).

Almost surely, 2^201550021 is an apocalyptic number.

It is an amenable number.

201550021 is a deficient number, since it is larger than the sum of its proper divisors (1).

201550021 is an equidigital number, since it uses as much as digits as its factorization.

201550021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 201550021 is about 14196.8313718238. The cubic root of 201550021 is about 586.3104244694.

The spelling of 201550021 in words is "two hundred one million, five hundred fifty thousand, twenty-one".