21241777 has 2 divisors, whose sum is σ = 21241778. Its totient is φ = 21241776.

The previous prime is 21241763. The next prime is 21241783. The reversal of 21241777 is 77714212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14107536 + 7134241 = 3756^2 + 2671^2 .

It is a cyclic number.

It is not a de Polignac number, because 21241777 - 2¹⁵ = 21209009 is a prime.

It is not a weakly prime, because it can be changed into another prime (21241477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620888 + 10620889.

It is an arithmetic number, because the mean of its divisors is an integer number (10620889).

Almost surely, 2^21241777 is an apocalyptic number.

It is an amenable number.

21241777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21241777 is an equidigital number, since it uses as much as digits as its factorization.

21241777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5488, while the sum is 31.

The square root of 21241777 is about 4608.8802327680. The cubic root of 21241777 is about 276.9471806912.

Adding to 21241777 its reverse (77714212), we get a palindrome (98955989).

The spelling of 21241777 in words is "twenty-one million, two hundred forty-one thousand, seven hundred seventy-seven".