21320479 has 2 divisors, whose sum is σ = 21320480. Its totient is φ = 21320478.

The previous prime is 21320447. The next prime is 21320491. The reversal of 21320479 is 97402312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21320479 - 2⁵ = 21320447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21320879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660239 + 10660240.

It is an arithmetic number, because the mean of its divisors is an integer number (10660240).

Almost surely, 2^21320479 is an apocalyptic number.

21320479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320479 is an equidigital number, since it uses as much as digits as its factorization.

21320479 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21320479 is about 4617.4104214375. The cubic root of 21320479 is about 277.2887941925.

The spelling of 21320479 in words is "twenty-one million, three hundred twenty thousand, four hundred seventy-nine".