21234487 has 2 divisors, whose sum is σ = 21234488. Its totient is φ = 21234486.

The previous prime is 21234469. The next prime is 21234509. The reversal of 21234487 is 78443212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21234487 - 2²³ = 12845879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21234427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617243 + 10617244.

It is an arithmetic number, because the mean of its divisors is an integer number (10617244).

Almost surely, 2^21234487 is an apocalyptic number.

21234487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21234487 is an equidigital number, since it uses as much as digits as its factorization.

21234487 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 31.

The square root of 21234487 is about 4608.0893003500. The cubic root of 21234487 is about 276.9154950817.

Adding to 21234487 its reverse (78443212), we get a palindrome (99677699).

The spelling of 21234487 in words is "twenty-one million, two hundred thirty-four thousand, four hundred eighty-seven".