26207999981 has 2 divisors, whose sum is σ = 26207999982. Its totient is φ = 26207999980.

The previous prime is 26207999963. The next prime is 26208000011. The reversal of 26207999981 is 18999970262.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13675197481 + 12532802500 = 116941^2 + 111950^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26207999981 is a prime.

It is a super-2 number, since 2×26207999981² (a number of 22 digits) contains 22 as substring.

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 (26207995981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13103999990 + 13103999991.

It is an arithmetic number, because the mean of its divisors is an integer number (13103999991).

Almost surely, 2^26207999981 is an apocalyptic number.

It is an amenable number.

26207999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

26207999981 is an equidigital number, since it uses as much as digits as its factorization.

26207999981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8817984, while the sum is 62.

The spelling of 26207999981 in words is "twenty-six billion, two hundred seven million, nine hundred ninety-nine thousand, nine hundred eighty-one".