261356112900 has 81 divisors (see below), whose sum is σ = 819254291583. Its totient is φ = 69690873600.

The previous prime is 261356112893. The next prime is 261356113037. The reversal of 261356112900 is 9211653162.

The square root of 261356112900 is 511230.

It is a perfect power (a square), and thus also a powerful number.

261356112900 is a `hidden beast` number, since 2 + 6 + 1 + 3 + 561 + 1 + 2 + 90 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 28391576004 + 232964536896 = 168498^2 + 482664^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 15328380 + ... + 15345420.

Almost surely, 2^261356112900 is an apocalyptic number.

261356112900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

261356112900 is the 511230-th square number.

It is an amenable number.

261356112900 is an abundant number, since it is smaller than the sum of its proper divisors (557898178683).

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

261356112900 is an equidigital number, since it uses as much as digits as its factorization.

261356112900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34102 (or 17051 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

Multiplying 261356112900 by its sum of digits (36), we get a square (9408820064400 = 3067380²).

261356112900 divided by its sum of digits (36) gives a square (7259892025 = 85205²).

The spelling of 261356112900 in words is "two hundred sixty-one billion, three hundred fifty-six million, one hundred twelve thousand, nine hundred".