21032287 has 2 divisors, whose sum is σ = 21032288. Its totient is φ = 21032286.

The previous prime is 21032273. The next prime is 21032293. The reversal of 21032287 is 78223012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21032287 - 2⁷ = 21032159 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21032237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10516143 + 10516144.

It is an arithmetic number, because the mean of its divisors is an integer number (10516144).

Almost surely, 2^21032287 is an apocalyptic number.

21032287 is a deficient number, since it is larger than the sum of its proper divisors (1).

21032287 is an equidigital number, since it uses as much as digits as its factorization.

21032287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 21032287 is about 4586.0971424513. The cubic root of 21032287 is about 276.0337379117.

Adding to 21032287 its reverse (78223012), we get a palindrome (99255299).

The spelling of 21032287 in words is "twenty-one million, thirty-two thousand, two hundred eighty-seven".