21237745049 has 2 divisors, whose sum is σ = 21237745050. Its totient is φ = 21237745048.

The previous prime is 21237744967. The next prime is 21237745051. The reversal of 21237745049 is 94054773212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18671309449 + 2566435600 = 136643^2 + 50660^2 .

It is a cyclic number.

It is not a de Polignac number, because 21237745049 - 2⁸ = 21237744793 is a prime.

It is a super-3 number, since 3×21237745049³ (a number of 32 digits) contains 333 as substring.

Together with 21237745051, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21237745849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10618872524 + 10618872525.

It is an arithmetic number, because the mean of its divisors is an integer number (10618872525).

Almost surely, 2^21237745049 is an apocalyptic number.

It is an amenable number.

21237745049 is a deficient number, since it is larger than the sum of its proper divisors (1).

21237745049 is an equidigital number, since it uses as much as digits as its factorization.

21237745049 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 423360, while the sum is 44.

The spelling of 21237745049 in words is "twenty-one billion, two hundred thirty-seven million, seven hundred forty-five thousand, forty-nine".