21782610869 has 2 divisors, whose sum is σ = 21782610870. Its totient is φ = 21782610868.

The previous prime is 21782610827. The next prime is 21782610887. The reversal of 21782610869 is 96801628712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15640753969 + 6141856900 = 125063^2 + 78370^2 .

It is a cyclic number.

It is not a de Polignac number, because 21782610869 - 2²⁴ = 21765833653 is a prime.

It is a super-2 number, since 2×21782610869² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21782610169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10891305434 + 10891305435.

It is an arithmetic number, because the mean of its divisors is an integer number (10891305435).

Almost surely, 2^21782610869 is an apocalyptic number.

It is an amenable number.

21782610869 is a deficient number, since it is larger than the sum of its proper divisors (1).

21782610869 is an equidigital number, since it uses as much as digits as its factorization.

21782610869 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 580608, while the sum is 50.

The spelling of 21782610869 in words is "twenty-one billion, seven hundred eighty-two million, six hundred ten thousand, eight hundred sixty-nine".