20287489 has 2 divisors, whose sum is σ = 20287490. Its totient is φ = 20287488.

The previous prime is 20287483. The next prime is 20287493. The reversal of 20287489 is 98478202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11614464 + 8673025 = 3408^2 + 2945^2 .

It is a cyclic number.

It is not a de Polignac number, because 20287489 - 2⁵ = 20287457 is a prime.

It is a super-3 number, since 3×20287489³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (20287483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10143744 + 10143745.

It is an arithmetic number, because the mean of its divisors is an integer number (10143745).

Almost surely, 2^20287489 is an apocalyptic number.

It is an amenable number.

20287489 is a deficient number, since it is larger than the sum of its proper divisors (1).

20287489 is an equidigital number, since it uses as much as digits as its factorization.

20287489 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64512, while the sum is 40.

The square root of 20287489 is about 4504.1635183461. The cubic root of 20287489 is about 272.7361877860.

The spelling of 20287489 in words is "twenty million, two hundred eighty-seven thousand, four hundred eighty-nine".