21260647 has 2 divisors, whose sum is σ = 21260648. Its totient is φ = 21260646.

The previous prime is 21260623. The next prime is 21260651. The reversal of 21260647 is 74606212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21260647 - 2²³ = 12872039 is a prime.

It is a super-2 number, since 2×21260647² = 904030221717218, which contains 22 as substring.

It is equal to p_1345357 and since 21260647 and 1345357 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21263647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630323 + 10630324.

It is an arithmetic number, because the mean of its divisors is an integer number (10630324).

Almost surely, 2^21260647 is an apocalyptic number.

21260647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21260647 is an equidigital number, since it uses as much as digits as its factorization.

21260647 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 21260647 is about 4610.9269133223. The cubic root of 21260647 is about 277.0291645191.

Adding to 21260647 its reverse (74606212), we get a palindrome (95866859).

The spelling of 21260647 in words is "twenty-one million, two hundred sixty thousand, six hundred forty-seven".