287972021 has 2 divisors, whose sum is σ = 287972022. Its totient is φ = 287972020.

The previous prime is 287972017. The next prime is 287972023. The reversal of 287972021 is 120279782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 279357796 + 8614225 = 16714^2 + 2935^2 .

It is a cyclic number.

It is not a de Polignac number, because 287972021 - 2² = 287972017 is a prime.

Together with 287972023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (287972023) 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 as a sum of consecutive naturals, namely, 143986010 + 143986011.

It is an arithmetic number, because the mean of its divisors is an integer number (143986011).

Almost surely, 2^287972021 is an apocalyptic number.

It is an amenable number.

287972021 is a deficient number, since it is larger than the sum of its proper divisors (1).

287972021 is an equidigital number, since it uses as much as digits as its factorization.

287972021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 287972021 is about 16969.7383892622. The cubic root of 287972021 is about 660.3640637571.

The spelling of 287972021 in words is "two hundred eighty-seven million, nine hundred seventy-two thousand, twenty-one".