261378801 has 18 divisors (see below), whose sum is σ = 398468850. Its totient is φ = 165079296.

The previous prime is 261378751. The next prime is 261378823. The reversal of 261378801 is 108873162.

It can be written as a sum of positive squares in only one way, i.e., 214593201 + 46785600 = 14649^2 + 6840^2 .

It is not a de Polignac number, because 261378801 - 2⁶ = 261378737 is a prime.

It is a super-2 number, since 2×261378801² = 136637755224395202, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261378301) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 36976 + ... + 43473.

Almost surely, 2^261378801 is an apocalyptic number.

It is an amenable number.

261378801 is a deficient number, since it is larger than the sum of its proper divisors (137090049).

261378801 is a wasteful number, since it uses less digits than its factorization.

261378801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80493 (or 80471 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 261378801 is about 16167.2137673750. The cubic root of 261378801 is about 639.3766725675.

The spelling of 261378801 in words is "two hundred sixty-one million, three hundred seventy-eight thousand, eight hundred one".