201521161 has 2 divisors, whose sum is σ = 201521162. Its totient is φ = 201521160.

The previous prime is 201521141. The next prime is 201521207. The reversal of 201521161 is 161125102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133541136 + 67980025 = 11556^2 + 8245^2 .

It is a cyclic number.

It is not a de Polignac number, because 201521161 - 2²¹ = 199424009 is a prime.

It is a super-2 number, since 2×201521161² = 81221556661575842, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (201521141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100760580 + 100760581.

It is an arithmetic number, because the mean of its divisors is an integer number (100760581).

Almost surely, 2^201521161 is an apocalyptic number.

It is an amenable number.

201521161 is a deficient number, since it is larger than the sum of its proper divisors (1).

201521161 is an equidigital number, since it uses as much as digits as its factorization.

201521161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 19.

The square root of 201521161 is about 14195.8149114449. The cubic root of 201521161 is about 586.2824384862.

Adding to 201521161 its reverse (161125102), we get a palindrome (362646263).

The spelling of 201521161 in words is "two hundred one million, five hundred twenty-one thousand, one hundred sixty-one".