287121681 has 48 divisors (see below), whose sum is σ = 518843520. Its totient is φ = 148642560.

The previous prime is 287121677. The next prime is 287121697. The reversal of 287121681 is 186121782.

It is not a de Polignac number, because 287121681 - 2² = 287121677 is a prime.

It is a super-2 number, since 2×287121681² = 164877719400531522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (287121181) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 282931 + ... + 283943.

It is an arithmetic number, because the mean of its divisors is an integer number (10809240).

Almost surely, 2^287121681 is an apocalyptic number.

287121681 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

287121681 is a deficient number, since it is larger than the sum of its proper divisors (231721839).

287121681 is a wasteful number, since it uses less digits than its factorization.

287121681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1446 (or 1443 counting only the distinct ones).

The product of its digits is 10752, while the sum is 36.

The square root of 287121681 is about 16944.6652666850. The cubic root of 287121681 is about 659.7134362016.

The spelling of 287121681 in words is "two hundred eighty-seven million, one hundred twenty-one thousand, six hundred eighty-one".