21117377 has 2 divisors, whose sum is σ = 21117378. Its totient is φ = 21117376.

The previous prime is 21117359. The next prime is 21117391. The reversal of 21117377 is 77371112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11282881 + 9834496 = 3359^2 + 3136^2 .

It is a cyclic number.

It is not a de Polignac number, because 21117377 - 2¹⁴ = 21100993 is a prime.

It is a super-2 number, since 2×21117377² = 891887222720258, which contains 22 as substring.

It is equal to p_1336916 and since 21117377 and 1336916 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21117347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10558688 + 10558689.

It is an arithmetic number, because the mean of its divisors is an integer number (10558689).

Almost surely, 2^21117377 is an apocalyptic number.

It is an amenable number.

21117377 is a deficient number, since it is larger than the sum of its proper divisors (1).

21117377 is an equidigital number, since it uses as much as digits as its factorization.

21117377 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2058, while the sum is 29.

The square root of 21117377 is about 4595.3647298120. The cubic root of 21117377 is about 276.4054855195.

Adding to 21117377 its reverse (77371112), we get a palindrome (98488489).

The spelling of 21117377 in words is "twenty-one million, one hundred seventeen thousand, three hundred seventy-seven".