21811429769 has 2 divisors, whose sum is σ = 21811429770. Its totient is φ = 21811429768.

The previous prime is 21811429751. The next prime is 21811429781. The reversal of 21811429769 is 96792411812.

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., 19622406400 + 2189023369 = 140080^2 + 46787^2 .

It is a cyclic number.

It is not a de Polignac number, because 21811429769 - 2¹⁶ = 21811364233 is a prime.

It is a super-2 number, since 2×21811429769² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21811429729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10905714884 + 10905714885.

It is an arithmetic number, because the mean of its divisors is an integer number (10905714885).

Almost surely, 2^21811429769 is an apocalyptic number.

It is an amenable number.

21811429769 is a deficient number, since it is larger than the sum of its proper divisors (1).

21811429769 is an equidigital number, since it uses as much as digits as its factorization.

21811429769 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 50.

The spelling of 21811429769 in words is "twenty-one billion, eight hundred eleven million, four hundred twenty-nine thousand, seven hundred sixty-nine".