21223487 has 2 divisors, whose sum is σ = 21223488. Its totient is φ = 21223486.

The previous prime is 21223483. The next prime is 21223507. The reversal of 21223487 is 78432212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21223487 - 2² = 21223483 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21223483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611743 + 10611744.

It is an arithmetic number, because the mean of its divisors is an integer number (10611744).

Almost surely, 2^21223487 is an apocalyptic number.

21223487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21223487 is an equidigital number, since it uses as much as digits as its factorization.

21223487 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 29.

The square root of 21223487 is about 4606.8955924787. The cubic root of 21223487 is about 276.8676704183.

Adding to 21223487 its reverse (78432212), we get a palindrome (99655699).

The spelling of 21223487 in words is "twenty-one million, two hundred twenty-three thousand, four hundred eighty-seven".