21797739877 has 2 divisors, whose sum is σ = 21797739878. Its totient is φ = 21797739876.

The previous prime is 21797739871. The next prime is 21797739919. The reversal of 21797739877 is 77893779712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21714674881 + 83064996 = 147359^2 + 9114^2 .

It is a cyclic number.

It is not a de Polignac number, because 21797739877 - 2¹⁹ = 21797215589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21797739871) 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, 10898869938 + 10898869939.

It is an arithmetic number, because the mean of its divisors is an integer number (10898869939).

Almost surely, 2^21797739877 is an apocalyptic number.

It is an amenable number.

21797739877 is a deficient number, since it is larger than the sum of its proper divisors (1).

21797739877 is an equidigital number, since it uses as much as digits as its factorization.

21797739877 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 65345616, while the sum is 67.

The spelling of 21797739877 in words is "twenty-one billion, seven hundred ninety-seven million, seven hundred thirty-nine thousand, eight hundred seventy-seven".