21261677 has 2 divisors, whose sum is σ = 21261678. Its totient is φ = 21261676.

The previous prime is 21261671. The next prime is 21261697. The reversal of 21261677 is 77616212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20376196 + 885481 = 4514^2 + 941^2 .

It is a cyclic number.

It is not a de Polignac number, because 21261677 - 2⁶ = 21261613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21261671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630838 + 10630839.

It is an arithmetic number, because the mean of its divisors is an integer number (10630839).

Almost surely, 2^21261677 is an apocalyptic number.

It is an amenable number.

21261677 is a deficient number, since it is larger than the sum of its proper divisors (1).

21261677 is an equidigital number, since it uses as much as digits as its factorization.

21261677 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056, while the sum is 32.

The square root of 21261677 is about 4611.0386031782. The cubic root of 21261677 is about 277.0336381275.

Adding to 21261677 its reverse (77616212), we get a palindrome (98877889).

The spelling of 21261677 in words is "twenty-one million, two hundred sixty-one thousand, six hundred seventy-seven".