280400121 has 24 divisors (see below), whose sum is σ = 410436936. Its totient is φ = 184450560.

The previous prime is 280400117. The next prime is 280400123. The reversal of 280400121 is 121004082.

It can be written as a sum of positive squares in 4 ways, for example, as 43086096 + 237314025 = 6564^2 + 15405^2 .

It is not a de Polignac number, because 280400121 - 2² = 280400117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 280400094 and 280400103.

It is not an unprimeable number, because it can be changed into a prime (280400123) 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, 297511 + ... + 298451.

It is an arithmetic number, because the mean of its divisors is an integer number (17101539).

Almost surely, 2^280400121 is an apocalyptic number.

It is an amenable number.

280400121 is a deficient number, since it is larger than the sum of its proper divisors (130036815).

280400121 is a wasteful number, since it uses less digits than its factorization.

280400121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1353 (or 1350 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 280400121 is about 16745.1521641340. The cubic root of 280400121 is about 654.5247380806.

The spelling of 280400121 in words is "two hundred eighty million, four hundred thousand, one hundred twenty-one".