21267270749 has 2 divisors, whose sum is σ = 21267270750. Its totient is φ = 21267270748.

The previous prime is 21267270709. The next prime is 21267270751. The reversal of 21267270749 is 94707276212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19967668249 + 1299602500 = 141307^2 + 36050^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21267270749 is a prime.

It is a super-2 number, since 2×21267270749² (a number of 21 digits) contains 22 as substring.

Together with 21267270751, 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 (21267270709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10633635374 + 10633635375.

It is an arithmetic number, because the mean of its divisors is an integer number (10633635375).

Almost surely, 2^21267270749 is an apocalyptic number.

It is an amenable number.

21267270749 is a deficient number, since it is larger than the sum of its proper divisors (1).

21267270749 is an equidigital number, since it uses as much as digits as its factorization.

21267270749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 592704, while the sum is 47.

The spelling of 21267270749 in words is "twenty-one billion, two hundred sixty-seven million, two hundred seventy thousand, seven hundred forty-nine".