127636721 has 2 divisors, whose sum is σ = 127636722. Its totient is φ = 127636720.

The previous prime is 127636669. The next prime is 127636723.

127636721 is nontrivially palindromic in base 10.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125776225 + 1860496 = 11215^2 + 1364^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 127636721 - 2⁶ = 127636657 is a prime.

It is a super-2 number, since 2×127636721² = 32582265095263682, which contains 22 as substring.

Together with 127636723, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (127636723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63818360 + 63818361.

It is an arithmetic number, because the mean of its divisors is an integer number (63818361).

Almost surely, 2^127636721 is an apocalyptic number.

It is an amenable number.

127636721 is a deficient number, since it is larger than the sum of its proper divisors (1).

127636721 is an equidigital number, since it uses as much as digits as its factorization.

127636721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 35.

The square root of 127636721 is about 11297.6422761566. The cubic root of 127636721 is about 503.4911943872.

The spelling of 127636721 in words is "one hundred twenty-seven million, six hundred thirty-six thousand, seven hundred twenty-one".