21777241 has 2 divisors, whose sum is σ = 21777242. Its totient is φ = 21777240.

The previous prime is 21777233. The next prime is 21777253. The reversal of 21777241 is 14277712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20967241 + 810000 = 4579^2 + 900^2 .

It is a cyclic number.

It is not a de Polignac number, because 21777241 - 2³ = 21777233 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21777341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10888620 + 10888621.

It is an arithmetic number, because the mean of its divisors is an integer number (10888621).

Almost surely, 2^21777241 is an apocalyptic number.

It is an amenable number.

21777241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21777241 is an equidigital number, since it uses as much as digits as its factorization.

21777241 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 21777241 is about 4666.6091544075. The cubic root of 21777241 is about 279.2549965484.

The spelling of 21777241 in words is "twenty-one million, seven hundred seventy-seven thousand, two hundred forty-one".