2155143550121 has 4 divisors (see below), whose sum is σ = 2155146500100. Its totient is φ = 2155140600144.

The previous prime is 2155143550097. The next prime is 2155143550127. The reversal of 2155143550121 is 1210553415512.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 890643300121 + 1264500250000 = 943739^2 + 1124500^2 .

It is a cyclic number.

It is not a de Polignac number, because 2155143550121 - 2³⁸ = 1880265643177 is a prime.

It is a super-2 number, since 2×2155143550121² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2155143550127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 522995 + ... + 2140983.

It is an arithmetic number, because the mean of its divisors is an integer number (538786625025).

Almost surely, 2^{2155143550121} is an apocalyptic number.

It is an amenable number.

2155143550121 is a deficient number, since it is larger than the sum of its proper divisors (2949979).

2155143550121 is a wasteful number, since it uses less digits than its factorization.

2155143550121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2949978.

The product of its (nonzero) digits is 30000, while the sum is 35.

Adding to 2155143550121 its reverse (1210553415512), we get a palindrome (3365696965633).

The spelling of 2155143550121 in words is "two trillion, one hundred fifty-five billion, one hundred forty-three million, five hundred fifty thousand, one hundred twenty-one".