21413647 has 2 divisors, whose sum is σ = 21413648. Its totient is φ = 21413646.

The previous prime is 21413641. The next prime is 21413677. The reversal of 21413647 is 74631412.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21413647 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21413641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10706823 + 10706824.

It is an arithmetic number, because the mean of its divisors is an integer number (10706824).

Almost surely, 2^21413647 is an apocalyptic number.

21413647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21413647 is an equidigital number, since it uses as much as digits as its factorization.

21413647 is an odious number, because the sum of its binary digits is odd.

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

The square root of 21413647 is about 4627.4881955549. The cubic root of 21413647 is about 277.6921138100.

It can be divided in two parts, 214 and 13647, that added together give a triangular number (13861 = T₁₆₆).

The spelling of 21413647 in words is "twenty-one million, four hundred thirteen thousand, six hundred forty-seven".