201121551 has 6 divisors (see below), whose sum is σ = 290508920. Its totient is φ = 134081028.

The previous prime is 201121519. The next prime is 201121561. The reversal of 201121551 is 155121102.

201121551 is a `hidden beast` number, since 2 + 0 + 112 + 1 + 551 = 666.

It is not a de Polignac number, because 201121551 - 2⁵ = 201121519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201121511) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11173411 + ... + 11173428.

Almost surely, 2^201121551 is an apocalyptic number.

201121551 is a deficient number, since it is larger than the sum of its proper divisors (89387369).

201121551 is a wasteful number, since it uses less digits than its factorization.

201121551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22346845 (or 22346842 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 18.

The square root of 201121551 is about 14181.7330041148. The cubic root of 201121551 is about 585.8946556278.

Adding to 201121551 its reverse (155121102), we get a palindrome (356242653).

The spelling of 201121551 in words is "two hundred one million, one hundred twenty-one thousand, five hundred fifty-one".