21426047 has 2 divisors, whose sum is σ = 21426048. Its totient is φ = 21426046.

The previous prime is 21426023. The next prime is 21426049. The reversal of 21426047 is 74062412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21426047 - 2¹⁰ = 21425023 is a prime.

Together with 21426049, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21426049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10713023 + 10713024.

It is an arithmetic number, because the mean of its divisors is an integer number (10713024).

Almost surely, 2^21426047 is an apocalyptic number.

21426047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21426047 is an equidigital number, since it uses as much as digits as its factorization.

21426047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 21426047 is about 4628.8278213820. The cubic root of 21426047 is about 277.7457045220.

Adding to 21426047 its reverse (74062412), we get a palindrome (95488459).

The spelling of 21426047 in words is "twenty-one million, four hundred twenty-six thousand, forty-seven".