21500489 has 2 divisors, whose sum is σ = 21500490. Its totient is φ = 21500488.

The previous prime is 21500483. The next prime is 21500491. The reversal of 21500489 is 98400512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18966025 + 2534464 = 4355^2 + 1592^2 .

It is a cyclic number.

It is not a de Polignac number, because 21500489 - 2¹⁶ = 21434953 is a prime.

Together with 21500491, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 11.

It is not a weakly prime, because it can be changed into another prime (21500483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10750244 + 10750245.

It is an arithmetic number, because the mean of its divisors is an integer number (10750245).

Almost surely, 2^21500489 is an apocalyptic number.

It is an amenable number.

21500489 is a deficient number, since it is larger than the sum of its proper divisors (1).

21500489 is an equidigital number, since it uses as much as digits as its factorization.

21500489 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 21500489 is about 4636.8619776741. The cubic root of 21500489 is about 278.0669964299.

The spelling of 21500489 in words is "twenty-one million, five hundred thousand, four hundred eighty-nine".