280643979 has 16 divisors (see below), whose sum is σ = 466525440. Its totient is φ = 145788960.

The previous prime is 280643971. The next prime is 280644029. The reversal of 280643979 is 979346082.

It is not a de Polignac number, because 280643979 - 2³ = 280643971 is a prime.

It is a super-2 number, since 2×280643979² = 157522085897904882, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (280643971) 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 in 15 ways as a sum of consecutive naturals, for example, 607224 + ... + 607685.

It is an arithmetic number, because the mean of its divisors is an integer number (29157840).

Almost surely, 2^280643979 is an apocalyptic number.

280643979 is a deficient number, since it is larger than the sum of its proper divisors (185881461).

280643979 is a wasteful number, since it uses less digits than its factorization.

280643979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1214930.

The product of its (nonzero) digits is 653184, while the sum is 48.

The square root of 280643979 is about 16752.4320323946. The cubic root of 280643979 is about 654.7144251669.

The spelling of 280643979 in words is "two hundred eighty million, six hundred forty-three thousand, nine hundred seventy-nine".