261526270021 has 4 divisors (see below), whose sum is σ = 269962601344. Its totient is φ = 253089938700.

The previous prime is 261526270001. The next prime is 261526270129. The reversal of 261526270021 is 120072625162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 261526270021 - 2¹⁷ = 261526138949 is a prime.

It is a super-2 number, since 2×261526270021² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261526270001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4218165615 + ... + 4218165676.

It is an arithmetic number, because the mean of its divisors is an integer number (67490650336).

Almost surely, 2^261526270021 is an apocalyptic number.

It is an amenable number.

261526270021 is a deficient number, since it is larger than the sum of its proper divisors (8436331323).

261526270021 is an equidigital number, since it uses as much as digits as its factorization.

261526270021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8436331322.

The product of its (nonzero) digits is 20160, while the sum is 34.

Adding to 261526270021 its reverse (120072625162), we get a palindrome (381598895183).

The spelling of 261526270021 in words is "two hundred sixty-one billion, five hundred twenty-six million, two hundred seventy thousand, twenty-one".