281979640 has 32 divisors (see below), whose sum is σ = 637108560. Its totient is φ = 112320000.

The previous prime is 281979631. The next prime is 281979641. The reversal of 281979640 is 46979182.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (281979641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4986 + ... + 24265.

Almost surely, 2^281979640 is an apocalyptic number.

281979640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

281979640 is an abundant number, since it is smaller than the sum of its proper divisors (355128920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

281979640 is a wasteful number, since it uses less digits than its factorization.

281979640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29503 (or 29499 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 46.

The square root of 281979640 is about 16792.2494026262. The cubic root of 281979640 is about 655.7514364161.

The spelling of 281979640 in words is "two hundred eighty-one million, nine hundred seventy-nine thousand, six hundred forty".