21695312077861 has 2 divisors, whose sum is σ = 21695312077862. Its totient is φ = 21695312077860.

The previous prime is 21695312077763. The next prime is 21695312077871. The reversal of 21695312077861 is 16877021359612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13382383341636 + 8312928736225 = 3658194^2 + 2883215^2 .

It is a cyclic number.

It is not a de Polignac number, because 21695312077861 - 2⁹ = 21695312077349 is a prime.

It is a super-3 number, since 3×21695312077861³ (a number of 41 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21695312077796 and 21695312077805.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21695312077871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10847656038930 + 10847656038931.

It is an arithmetic number, because the mean of its divisors is an integer number (10847656038931).

Almost surely, 2^{21695312077861} is an apocalyptic number.

It is an amenable number.

21695312077861 is a deficient number, since it is larger than the sum of its proper divisors (1).

21695312077861 is an equidigital number, since it uses as much as digits as its factorization.

21695312077861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7620480, while the sum is 58.

The spelling of 21695312077861 in words is "twenty-one trillion, six hundred ninety-five billion, three hundred twelve million, seventy-seven thousand, eight hundred sixty-one".