261005135400 has 72 divisors (see below), whose sum is σ = 876542252430. Its totient is φ = 69601368960.

The previous prime is 261005135389. The next prime is 261005135411. The reversal of 261005135400 is 4531500162.

261005135400 is a `hidden beast` number, since 2 + 6 + 100 + 5 + 13 + 540 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (261005135389) and next prime (261005135411).

It can be written as a sum of positive squares in 3 ways, for example, as 252644959044 + 8360176356 = 502638^2 + 91434^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 72499627 + ... + 72503226.

Almost surely, 2^261005135400 is an apocalyptic number.

261005135400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261005135400 is an abundant number, since it is smaller than the sum of its proper divisors (615537117030).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261005135400 is a wasteful number, since it uses less digits than its factorization.

261005135400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145002875 (or 145002863 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

Adding to 261005135400 its reverse (4531500162), we get a palindrome (265536635562).

The spelling of 261005135400 in words is "two hundred sixty-one billion, five million, one hundred thirty-five thousand, four hundred".