21272120449 has 2 divisors, whose sum is σ = 21272120450. Its totient is φ = 21272120448.

The previous prime is 21272120447. The next prime is 21272120497. The reversal of 21272120449 is 94402127212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13732324225 + 7539796224 = 117185^2 + 86832^2 .

It is a cyclic number.

It is not a de Polignac number, because 21272120449 - 2¹ = 21272120447 is a prime.

Together with 21272120447, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21272120447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10636060224 + 10636060225.

It is an arithmetic number, because the mean of its divisors is an integer number (10636060225).

Almost surely, 2^21272120449 is an apocalyptic number.

It is an amenable number.

21272120449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21272120449 is an equidigital number, since it uses as much as digits as its factorization.

21272120449 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 34.

The spelling of 21272120449 in words is "twenty-one billion, two hundred seventy-two million, one hundred twenty thousand, four hundred forty-nine".