201523421561 has 24 divisors (see below), whose sum is σ = 255769488000. Its totient is φ = 157011036000.

The previous prime is 201523421551. The next prime is 201523421563. The reversal of 201523421561 is 165124325102.

It is not a de Polignac number, because 201523421561 - 2¹⁴ = 201523405177 is a prime.

It is a super-2 number, since 2×201523421561² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (201523421563) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5235536 + ... + 5273886.

It is an arithmetic number, because the mean of its divisors is an integer number (10657062000).

Almost surely, 2^201523421561 is an apocalyptic number.

It is an amenable number.

201523421561 is a deficient number, since it is larger than the sum of its proper divisors (54246066439).

201523421561 is a wasteful number, since it uses less digits than its factorization.

201523421561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48125 (or 48118 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 32.

Adding to 201523421561 its reverse (165124325102), we get a palindrome (366647746663).

The spelling of 201523421561 in words is "two hundred one billion, five hundred twenty-three million, four hundred twenty-one thousand, five hundred sixty-one".