21865741 has 2 divisors, whose sum is σ = 21865742. Its totient is φ = 21865740.

The previous prime is 21865721. The next prime is 21865759. The reversal of 21865741 is 14756812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16362025 + 5503716 = 4045^2 + 2346^2 .

It is a cyclic number.

It is not a de Polignac number, because 21865741 - 2⁹ = 21865229 is a prime.

It is a super-2 number, since 2×21865741² = 956221258958162, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21865697 and 21865706.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21865721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10932870 + 10932871.

It is an arithmetic number, because the mean of its divisors is an integer number (10932871).

Almost surely, 2^21865741 is an apocalyptic number.

It is an amenable number.

21865741 is a deficient number, since it is larger than the sum of its proper divisors (1).

21865741 is an equidigital number, since it uses as much as digits as its factorization.

21865741 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 34.

The square root of 21865741 is about 4676.0817999689. The cubic root of 21865741 is about 279.6327711293.

The spelling of 21865741 in words is "twenty-one million, eight hundred sixty-five thousand, seven hundred forty-one".