26542391021 has 2 divisors, whose sum is σ = 26542391022. Its totient is φ = 26542391020.

The previous prime is 26542390999. The next prime is 26542391041. The reversal of 26542391021 is 12019324562.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16062774121 + 10479616900 = 126739^2 + 102370^2 .

It is a cyclic number.

It is not a de Polignac number, because 26542391021 - 2⁶ = 26542390957 is a prime.

It is a super-2 number, since 2×26542391021² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26542391041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13271195510 + 13271195511.

It is an arithmetic number, because the mean of its divisors is an integer number (13271195511).

Almost surely, 2^26542391021 is an apocalyptic number.

It is an amenable number.

26542391021 is a deficient number, since it is larger than the sum of its proper divisors (1).

26542391021 is an equidigital number, since it uses as much as digits as its factorization.

26542391021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 35.

The spelling of 26542391021 in words is "twenty-six billion, five hundred forty-two million, three hundred ninety-one thousand, twenty-one".