20287391 has 2 divisors, whose sum is σ = 20287392. Its totient is φ = 20287390.

The previous prime is 20287373. The next prime is 20287411. The reversal of 20287391 is 19378202.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20287391 - 2¹⁰ = 20286367 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20287301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10143695 + 10143696.

It is an arithmetic number, because the mean of its divisors is an integer number (10143696).

Almost surely, 2^20287391 is an apocalyptic number.

20287391 is a deficient number, since it is larger than the sum of its proper divisors (1).

20287391 is an equidigital number, since it uses as much as digits as its factorization.

20287391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 20287391 is about 4504.1526395095. The cubic root of 20287391 is about 272.7357486288.

The spelling of 20287391 in words is "twenty million, two hundred eighty-seven thousand, three hundred ninety-one".