21277731247 has 2 divisors, whose sum is σ = 21277731248. Its totient is φ = 21277731246.

The previous prime is 21277731239. The next prime is 21277731263. The reversal of 21277731247 is 74213777212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21277731247 - 2³ = 21277731239 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21277731047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10638865623 + 10638865624.

It is an arithmetic number, because the mean of its divisors is an integer number (10638865624).

Almost surely, 2^21277731247 is an apocalyptic number.

21277731247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21277731247 is an equidigital number, since it uses as much as digits as its factorization.

21277731247 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 230496, while the sum is 43.

The spelling of 21277731247 in words is "twenty-one billion, two hundred seventy-seven million, seven hundred thirty-one thousand, two hundred forty-seven".