21415847 has 2 divisors, whose sum is σ = 21415848. Its totient is φ = 21415846.

The previous prime is 21415841. The next prime is 21415871. The reversal of 21415847 is 74851412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21415847 - 2¹⁸ = 21153703 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21415841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10707923 + 10707924.

It is an arithmetic number, because the mean of its divisors is an integer number (10707924).

Almost surely, 2^21415847 is an apocalyptic number.

21415847 is a deficient number, since it is larger than the sum of its proper divisors (1).

21415847 is an equidigital number, since it uses as much as digits as its factorization.

21415847 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8960, while the sum is 32.

The square root of 21415847 is about 4627.7258994024. The cubic root of 21415847 is about 277.7016233489.

It can be divided in two parts, 214 and 15847, that added together give a palindrome (16061).

The spelling of 21415847 in words is "twenty-one million, four hundred fifteen thousand, eight hundred forty-seven".