21877241 has 2 divisors, whose sum is σ = 21877242. Its totient is φ = 21877240.

The previous prime is 21877199. The next prime is 21877253. The reversal of 21877241 is 14277812.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16605625 + 5271616 = 4075^2 + 2296^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21877241 is a prime.

It is a super-2 number, since 2×21877241² = 957227347544162, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21877198 and 21877207.

It is not a weakly prime, because it can be changed into another prime (21877291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10938620 + 10938621.

It is an arithmetic number, because the mean of its divisors is an integer number (10938621).

Almost surely, 2^21877241 is an apocalyptic number.

It is an amenable number.

21877241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21877241 is an equidigital number, since it uses as much as digits as its factorization.

21877241 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6272, while the sum is 32.

The square root of 21877241 is about 4677.3113003092. The cubic root of 21877241 is about 279.6817856015.

The spelling of 21877241 in words is "twenty-one million, eight hundred seventy-seven thousand, two hundred forty-one".