21243333487 has 2 divisors, whose sum is σ = 21243333488. Its totient is φ = 21243333486.

The previous prime is 21243333427. The next prime is 21243333511. The reversal of 21243333487 is 78433334212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21243333487 - 2¹⁹ = 21242809199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243333427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621666743 + 10621666744.

It is an arithmetic number, because the mean of its divisors is an integer number (10621666744).

Almost surely, 2^21243333487 is an apocalyptic number.

21243333487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243333487 is an equidigital number, since it uses as much as digits as its factorization.

21243333487 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 40.

Adding to 21243333487 its reverse (78433334212), we get a palindrome (99676667699).

The spelling of 21243333487 in words is "twenty-one billion, two hundred forty-three million, three hundred thirty-three thousand, four hundred eighty-seven".