21601759 has 2 divisors, whose sum is σ = 21601760. Its totient is φ = 21601758.

The previous prime is 21601757. The next prime is 21601763. The reversal of 21601759 is 95710612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21601759 - 2¹ = 21601757 is a prime.

Together with 21601757, it forms a pair of twin primes.

It is a plaindrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 21601759.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21601757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10800879 + 10800880.

It is an arithmetic number, because the mean of its divisors is an integer number (10800880).

Almost surely, 2^21601759 is an apocalyptic number.

21601759 is a deficient number, since it is larger than the sum of its proper divisors (1).

21601759 is an equidigital number, since it uses as much as digits as its factorization.

21601759 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3780, while the sum is 31.

The square root of 21601759 is about 4647.7692498660. The cubic root of 21601759 is about 278.5028895845.

The spelling of 21601759 in words is "twenty-one million, six hundred one thousand, seven hundred fifty-nine".