281020121 has 4 divisors (see below), whose sum is σ = 290710500. Its totient is φ = 271329744.

The previous prime is 281020087. The next prime is 281020133. The reversal of 281020121 is 121020182.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121020182 = 2 ⋅60510091.

It can be written as a sum of positive squares in 2 ways, for example, as 54096025 + 226924096 = 7355^2 + 15064^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-281020121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 281020121.

It is not an unprimeable number, because it can be changed into a prime (281020171) 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, 4845146 + ... + 4845203.

It is an arithmetic number, because the mean of its divisors is an integer number (72677625).

Almost surely, 2^281020121 is an apocalyptic number.

It is an amenable number.

281020121 is a deficient number, since it is larger than the sum of its proper divisors (9690379).

281020121 is an equidigital number, since it uses as much as digits as its factorization.

281020121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9690378.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 281020121 is about 16763.6547626107. The cubic root of 281020121 is about 655.0067951823.

The spelling of 281020121 in words is "two hundred eighty-one million, twenty thousand, one hundred twenty-one".