21919741 has 2 divisors, whose sum is σ = 21919742. Its totient is φ = 21919740.

The previous prime is 21919669. The next prime is 21919753. The reversal of 21919741 is 14791912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12744900 + 9174841 = 3570^2 + 3029^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21919741 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21919697 and 21919706.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21919771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10959870 + 10959871.

It is an arithmetic number, because the mean of its divisors is an integer number (10959871).

Almost surely, 2^21919741 is an apocalyptic number.

It is an amenable number.

21919741 is a deficient number, since it is larger than the sum of its proper divisors (1).

21919741 is an equidigital number, since it uses as much as digits as its factorization.

21919741 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 34.

The square root of 21919741 is about 4681.8523043770. The cubic root of 21919741 is about 279.8627771483.

The spelling of 21919741 in words is "twenty-one million, nine hundred nineteen thousand, seven hundred forty-one".