201515421123 has 24 divisors (see below), whose sum is σ = 291506127120. Its totient is φ = 134146091520.

The previous prime is 201515421119. The next prime is 201515421157. The reversal of 201515421123 is 321124515102.

It is a happy number.

201515421123 is a `hidden beast` number, since 2 + 0 + 1 + 5 + 1 + 542 + 112 + 3 = 666.

It is not a de Polignac number, because 201515421123 - 2² = 201515421119 is a prime.

It is a super-2 number, since 2×201515421123² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (201515421103) 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, 21160603 + ... + 21170123.

It is an arithmetic number, because the mean of its divisors is an integer number (12146088630).

Almost surely, 2^201515421123 is an apocalyptic number.

201515421123 is a deficient number, since it is larger than the sum of its proper divisors (89990705997).

201515421123 is a wasteful number, since it uses less digits than its factorization.

201515421123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12739 (or 12736 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

Adding to 201515421123 its reverse (321124515102), we get a palindrome (522639936225).

The spelling of 201515421123 in words is "two hundred one billion, five hundred fifteen million, four hundred twenty-one thousand, one hundred twenty-three".