201641551021 has 2 divisors, whose sum is σ = 201641551022. Its totient is φ = 201641551020.

The previous prime is 201641551003. The next prime is 201641551073. The reversal of 201641551021 is 120155146102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198571836996 + 3069714025 = 445614^2 + 55405^2 .

It is a cyclic number.

It is not a de Polignac number, because 201641551021 - 2⁷ = 201641550893 is a prime.

It is a super-2 number, since 2×201641551021² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201641551091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100820775510 + 100820775511.

It is an arithmetic number, because the mean of its divisors is an integer number (100820775511).

Almost surely, 2^201641551021 is an apocalyptic number.

It is an amenable number.

201641551021 is a deficient number, since it is larger than the sum of its proper divisors (1).

201641551021 is an equidigital number, since it uses as much as digits as its factorization.

201641551021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2400, while the sum is 28.

Adding to 201641551021 its reverse (120155146102), we get a palindrome (321796697123).

The spelling of 201641551021 in words is "two hundred one billion, six hundred forty-one million, five hundred fifty-one thousand, twenty-one".