201521154217 has 2 divisors, whose sum is σ = 201521154218. Its totient is φ = 201521154216.

The previous prime is 201521154113. The next prime is 201521154221. The reversal of 201521154217 is 712451125102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 117618817936 + 83902336281 = 342956^2 + 289659^2 .

It is a cyclic number.

It is not a de Polignac number, because 201521154217 - 2³⁵ = 167161415849 is a prime.

It is a super-2 number, since 2×201521154217² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (201521154227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100760577108 + 100760577109.

It is an arithmetic number, because the mean of its divisors is an integer number (100760577109).

Almost surely, 2^201521154217 is an apocalyptic number.

It is an amenable number.

201521154217 is a deficient number, since it is larger than the sum of its proper divisors (1).

201521154217 is an equidigital number, since it uses as much as digits as its factorization.

201521154217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5600, while the sum is 31.

Adding to 201521154217 its reverse (712451125102), we get a palindrome (913972279319).

The spelling of 201521154217 in words is "two hundred one billion, five hundred twenty-one million, one hundred fifty-four thousand, two hundred seventeen".