21116477 has 2 divisors, whose sum is σ = 21116478. Its totient is φ = 21116476.

The previous prime is 21116471. The next prime is 21116479. The reversal of 21116477 is 77461112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20259001 + 857476 = 4501^2 + 926^2 .

It is a cyclic number.

It is not a de Polignac number, because 21116477 - 2¹⁰ = 21115453 is a prime.

Together with 21116479, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21116471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10558238 + 10558239.

It is an arithmetic number, because the mean of its divisors is an integer number (10558239).

Almost surely, 2^21116477 is an apocalyptic number.

It is an amenable number.

21116477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21116477 is an equidigital number, since it uses as much as digits as its factorization.

21116477 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2352, while the sum is 29.

The square root of 21116477 is about 4595.2668040061. The cubic root of 21116477 is about 276.4015587618.

Adding to 21116477 its reverse (77461112), we get a palindrome (98577589).

The spelling of 21116477 in words is "twenty-one million, one hundred sixteen thousand, four hundred seventy-seven".