21127797 has 20 divisors (see below), whose sum is σ = 31864140. Its totient is φ = 13950144.

The previous prime is 21127783. The next prime is 21127817. The reversal of 21127797 is 79772112.

It can be written as a sum of positive squares in 2 ways, for example, as 6081156 + 15046641 = 2466^2 + 3879^2 .

It is not a de Polignac number, because 21127797 - 2⁴ = 21127781 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21127727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7633 + ... + 10025.

It is an arithmetic number, because the mean of its divisors is an integer number (1593207).

Almost surely, 2^21127797 is an apocalyptic number.

21127797 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21127797 is a deficient number, since it is larger than the sum of its proper divisors (10736343).

21127797 is a wasteful number, since it uses less digits than its factorization.

21127797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2514 (or 2505 counting only the distinct ones).

The product of its digits is 12348, while the sum is 36.

The square root of 21127797 is about 4596.4983411288. The cubic root of 21127797 is about 276.4509405267.

The spelling of 21127797 in words is "twenty-one million, one hundred twenty-seven thousand, seven hundred ninety-seven".