21442741 has 2 divisors, whose sum is σ = 21442742. Its totient is φ = 21442740.

The previous prime is 21442717. The next prime is 21442753. The reversal of 21442741 is 14724412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18309841 + 3132900 = 4279^2 + 1770^2 .

It is a cyclic number.

It is not a de Polignac number, because 21442741 - 2⁹ = 21442229 is a prime.

It is a super-2 number, since 2×21442741² = 919582283186162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21449741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721370 + 10721371.

It is an arithmetic number, because the mean of its divisors is an integer number (10721371).

Almost surely, 2^21442741 is an apocalyptic number.

It is an amenable number.

21442741 is a deficient number, since it is larger than the sum of its proper divisors (1).

21442741 is an equidigital number, since it uses as much as digits as its factorization.

21442741 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1792, while the sum is 25.

The square root of 21442741 is about 4630.6307345760. The cubic root of 21442741 is about 277.8178205326.

The spelling of 21442741 in words is "twenty-one million, four hundred forty-two thousand, seven hundred forty-one".