21620359 has 2 divisors, whose sum is σ = 21620360. Its totient is φ = 21620358.

The previous prime is 21620323. The next prime is 21620369. The reversal of 21620359 is 95302612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21620359 - 2¹⁷ = 21489287 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21620369) 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, 10810179 + 10810180.

It is an arithmetic number, because the mean of its divisors is an integer number (10810180).

Almost surely, 2^21620359 is an apocalyptic number.

21620359 is a deficient number, since it is larger than the sum of its proper divisors (1).

21620359 is an equidigital number, since it uses as much as digits as its factorization.

21620359 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 21620359 is about 4649.7697792471. The cubic root of 21620359 is about 278.5828007881.

The spelling of 21620359 in words is "twenty-one million, six hundred twenty thousand, three hundred fifty-nine".