21384679 has 2 divisors, whose sum is σ = 21384680. Its totient is φ = 21384678.

The previous prime is 21384673. The next prime is 21384719. The reversal of 21384679 is 97648312.

It is an a-pointer prime, because the next prime (21384719) can be obtained adding 21384679 to its sum of digits (40).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21384679 - 2⁵ = 21384647 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21384673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10692339 + 10692340.

It is an arithmetic number, because the mean of its divisors is an integer number (10692340).

Almost surely, 2^21384679 is an apocalyptic number.

21384679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21384679 is an equidigital number, since it uses as much as digits as its factorization.

21384679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 40.

The square root of 21384679 is about 4624.3571445121. The cubic root of 21384679 is about 277.5668383221.

The spelling of 21384679 in words is "twenty-one million, three hundred eighty-four thousand, six hundred seventy-nine".