280742921 has 2 divisors, whose sum is σ = 280742922. Its totient is φ = 280742920.

The previous prime is 280742909. The next prime is 280742941. The reversal of 280742921 is 129247082.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 241367296 + 39375625 = 15536^2 + 6275^2 .

It is a cyclic number.

It is not a de Polignac number, because 280742921 - 2⁶ = 280742857 is a prime.

It is a super-2 number, since 2×280742921² = 157633175383224482, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (280742941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140371460 + 140371461.

It is an arithmetic number, because the mean of its divisors is an integer number (140371461).

Almost surely, 2^280742921 is an apocalyptic number.

It is an amenable number.

280742921 is a deficient number, since it is larger than the sum of its proper divisors (1).

280742921 is an equidigital number, since it uses as much as digits as its factorization.

280742921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 280742921 is about 16755.3848359266. The cubic root of 280742921 is about 654.7913567342.

The spelling of 280742921 in words is "two hundred eighty million, seven hundred forty-two thousand, nine hundred twenty-one".