21877780493 has 2 divisors, whose sum is σ = 21877780494. Its totient is φ = 21877780492.

The previous prime is 21877780469. The next prime is 21877780531. The reversal of 21877780493 is 39408777812.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21875001604 + 2778889 = 147902^2 + 1667^2 .

It is a cyclic number.

It is not a de Polignac number, because 21877780493 - 2⁶ = 21877780429 is a prime.

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 (21877780433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10938890246 + 10938890247.

It is an arithmetic number, because the mean of its divisors is an integer number (10938890247).

Almost surely, 2^21877780493 is an apocalyptic number.

It is an amenable number.

21877780493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21877780493 is an equidigital number, since it uses as much as digits as its factorization.

21877780493 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4741632, while the sum is 56.

The spelling of 21877780493 in words is "twenty-one billion, eight hundred seventy-seven million, seven hundred eighty thousand, four hundred ninety-three".