21093777 has 10 divisors (see below), whose sum is σ = 31510578. Its totient is φ = 14062464.

The previous prime is 21093773. The next prime is 21093799. The reversal of 21093777 is 77739012.

It can be written as a sum of positive squares in only one way, i.e., 18584721 + 2509056 = 4311^2 + 1584^2 .

It is not a de Polignac number, because 21093777 - 2² = 21093773 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21093773) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 130128 + ... + 130289.

Almost surely, 2^21093777 is an apocalyptic number.

21093777 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21093777 is a deficient number, since it is larger than the sum of its proper divisors (10416801).

21093777 is an equidigital number, since it uses as much as digits as its factorization.

21093777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260429 (or 260420 counting only the distinct ones).

The product of its (nonzero) digits is 18522, while the sum is 36.

The square root of 21093777 is about 4592.7962071052. The cubic root of 21093777 is about 276.3024802870.

It can be divided in two parts, 2109 and 3777, that added together give a triangular number (5886 = T₁₀₈).

The spelling of 21093777 in words is "twenty-one million, ninety-three thousand, seven hundred seventy-seven".