21791677 has 2 divisors, whose sum is σ = 21791678. Its totient is φ = 21791676.

The previous prime is 21791657. The next prime is 21791681. The reversal of 21791677 is 77619712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21288996 + 502681 = 4614^2 + 709^2 .

It is a cyclic number.

It is not a de Polignac number, because 21791677 - 2¹⁵ = 21758909 is a prime.

It is a plaindrome in base 11.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21791617) 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, 10895838 + 10895839.

It is an arithmetic number, because the mean of its divisors is an integer number (10895839).

Almost surely, 2^21791677 is an apocalyptic number.

It is an amenable number.

21791677 is a deficient number, since it is larger than the sum of its proper divisors (1).

21791677 is an equidigital number, since it uses as much as digits as its factorization.

21791677 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37044, while the sum is 40.

The square root of 21791677 is about 4668.1556315102. The cubic root of 21791677 is about 279.3166883957.

The spelling of 21791677 in words is "twenty-one million, seven hundred ninety-one thousand, six hundred seventy-seven".