21739741 has 2 divisors, whose sum is σ = 21739742. Its totient is φ = 21739740.

The previous prime is 21739693. The next prime is 21739747. The reversal of 21739741 is 14793712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16080100 + 5659641 = 4010^2 + 2379^2 .

It is a cyclic number.

It is not a de Polignac number, because 21739741 - 2¹¹ = 21737693 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21739697 and 21739706.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21739747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10869870 + 10869871.

It is an arithmetic number, because the mean of its divisors is an integer number (10869871).

Almost surely, 2^21739741 is an apocalyptic number.

It is an amenable number.

21739741 is a deficient number, since it is larger than the sum of its proper divisors (1).

21739741 is an equidigital number, since it uses as much as digits as its factorization.

21739741 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10584, while the sum is 34.

The square root of 21739741 is about 4662.5895165669. The cubic root of 21739741 is about 279.0946138347.

The spelling of 21739741 in words is "twenty-one million, seven hundred thirty-nine thousand, seven hundred forty-one".