21742753 has 2 divisors, whose sum is σ = 21742754. Its totient is φ = 21742752.

The previous prime is 21742727. The next prime is 21742757. The reversal of 21742753 is 35724712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16064064 + 5678689 = 4008^2 + 2383^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21742753 is a prime.

It is not a weakly prime, because it can be changed into another prime (21742757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10871376 + 10871377.

It is an arithmetic number, because the mean of its divisors is an integer number (10871377).

Almost surely, 2^21742753 is an apocalyptic number.

It is an amenable number.

21742753 is a deficient number, since it is larger than the sum of its proper divisors (1).

21742753 is an equidigital number, since it uses as much as digits as its factorization.

21742753 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11760, while the sum is 31.

The square root of 21742753 is about 4662.9125018598. The cubic root of 21742753 is about 279.1075025831.

The spelling of 21742753 in words is "twenty-one million, seven hundred forty-two thousand, seven hundred fifty-three".