261553237026625 has 32 divisors (see below), whose sum is σ = 335598346111392. Its totient is φ = 203370105369600.

The previous prime is 261553237026611. The next prime is 261553237026647. The reversal of 261553237026625 is 526620732355162.

It can be written as a sum of positive squares in 16 ways, for example, as 217913366848321 + 43639870178304 = 14761889^2 + 6606048^2 .

It is not a de Polignac number, because 261553237026625 - 2¹¹ = 261553237024577 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 25843564 + ... + 34510813.

It is an arithmetic number, because the mean of its divisors is an integer number (10487448315981).

Almost surely, 2^{261553237026625} is an apocalyptic number.

261553237026625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261553237026625 is a deficient number, since it is larger than the sum of its proper divisors (74045109084767).

261553237026625 is an equidigital number, since it uses as much as digits as its factorization.

261553237026625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60355366 (or 60355356 counting only the distinct ones).

The product of its (nonzero) digits is 27216000, while the sum is 55.

The spelling of 261553237026625 in words is "two hundred sixty-one trillion, five hundred fifty-three billion, two hundred thirty-seven million, twenty-six thousand, six hundred twenty-five".