21434047 has 2 divisors, whose sum is σ = 21434048. Its totient is φ = 21434046.

The previous prime is 21434029. The next prime is 21434053. The reversal of 21434047 is 74043412.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21434047 is a prime.

It is equal to p_1355650 and since 21434047 and 1355650 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 (21434027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10717023 + 10717024.

It is an arithmetic number, because the mean of its divisors is an integer number (10717024).

Almost surely, 2^21434047 is an apocalyptic number.

21434047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21434047 is an equidigital number, since it uses as much as digits as its factorization.

21434047 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 25.

The square root of 21434047 is about 4629.6918903962. The cubic root of 21434047 is about 277.7802682029.

Adding to 21434047 its reverse (74043412), we get a palindrome (95477459).

The spelling of 21434047 in words is "twenty-one million, four hundred thirty-four thousand, forty-seven".