280687720921 has 2 divisors, whose sum is σ = 280687720922. Its totient is φ = 280687720920.

The previous prime is 280687720889. The next prime is 280687720981. The reversal of 280687720921 is 129027786082.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 256176687321 + 24511033600 = 506139^2 + 156560^2 .

It is a cyclic number.

It is not a de Polignac number, because 280687720921 - 2⁵ = 280687720889 is a prime.

It is not a weakly prime, because it can be changed into another prime (280687720981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140343860460 + 140343860461.

It is an arithmetic number, because the mean of its divisors is an integer number (140343860461).

Almost surely, 2^280687720921 is an apocalyptic number.

It is an amenable number.

280687720921 is a deficient number, since it is larger than the sum of its proper divisors (1).

280687720921 is an equidigital number, since it uses as much as digits as its factorization.

280687720921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1354752, while the sum is 52.

The spelling of 280687720921 in words is "two hundred eighty billion, six hundred eighty-seven million, seven hundred twenty thousand, nine hundred twenty-one".