287537981 has 2 divisors, whose sum is σ = 287537982. Its totient is φ = 287537980.

The previous prime is 287537977. The next prime is 287538029. The reversal of 287537981 is 189735782.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 147233956 + 140304025 = 12134^2 + 11845^2 .

It is a cyclic number.

It is not a de Polignac number, because 287537981 - 2² = 287537977 is a prime.

It is a super-2 number, since 2×287537981² = 165356181035112722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (287537941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 143768990 + 143768991.

It is an arithmetic number, because the mean of its divisors is an integer number (143768991).

Almost surely, 2^287537981 is an apocalyptic number.

It is an amenable number.

287537981 is a deficient number, since it is larger than the sum of its proper divisors (1).

287537981 is an equidigital number, since it uses as much as digits as its factorization.

287537981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 846720, while the sum is 50.

The square root of 287537981 is about 16956.9449194128. The cubic root of 287537981 is about 660.0321234747.

The spelling of 287537981 in words is "two hundred eighty-seven million, five hundred thirty-seven thousand, nine hundred eighty-one".