21867800681 has 2 divisors, whose sum is σ = 21867800682. Its totient is φ = 21867800680.

The previous prime is 21867800677. The next prime is 21867800719. The reversal of 21867800681 is 18600876812.

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., 18059059456 + 3808741225 = 134384^2 + 61715^2 .

It is a cyclic number.

It is not a de Polignac number, because 21867800681 - 2² = 21867800677 is a prime.

It is a super-2 number, since 2×21867800681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21867800641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10933900340 + 10933900341.

It is an arithmetic number, because the mean of its divisors is an integer number (10933900341).

Almost surely, 2^21867800681 is an apocalyptic number.

It is an amenable number.

21867800681 is a deficient number, since it is larger than the sum of its proper divisors (1).

21867800681 is an equidigital number, since it uses as much as digits as its factorization.

21867800681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 258048, while the sum is 47.

The spelling of 21867800681 in words is "twenty-one billion, eight hundred sixty-seven million, eight hundred thousand, six hundred eighty-one".