21234177749 has 2 divisors, whose sum is σ = 21234177750. Its totient is φ = 21234177748.

The previous prime is 21234177733. The next prime is 21234177779. The reversal of 21234177749 is 94777143212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21233735524 + 442225 = 145718^2 + 665^2 .

It is a cyclic number.

It is not a de Polignac number, because 21234177749 - 2⁴ = 21234177733 is a prime.

It is a super-2 number, since 2×21234177749² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21234177779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617088874 + 10617088875.

It is an arithmetic number, because the mean of its divisors is an integer number (10617088875).

Almost surely, 2^21234177749 is an apocalyptic number.

It is an amenable number.

21234177749 is a deficient number, since it is larger than the sum of its proper divisors (1).

21234177749 is an equidigital number, since it uses as much as digits as its factorization.

21234177749 is an odious number, because the sum of its binary digits is odd.

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

The spelling of 21234177749 in words is "twenty-one billion, two hundred thirty-four million, one hundred seventy-seven thousand, seven hundred forty-nine".