261299001600 has 2160 divisors, whose sum is σ = 1236540856320. Its totient is φ = 52951449600.

The previous prime is 261299001599. The next prime is 261299001637. The reversal of 261299001600 is 6100992162.

261299001600 is a `hidden beast` number, since 26 + 1 + 29 + 9 + 0 + 0 + 1 + 600 = 666.

It is a tau number, because it is divible by the number of its divisors (2160).

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 239 ways as a sum of consecutive naturals, for example, 1368057505 + ... + 1368057695.

Almost surely, 2^261299001600 is an apocalyptic number.

261299001600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261299001600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (618270428160).

261299001600 is an abundant number, since it is smaller than the sum of its proper divisors (975241854720).

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

261299001600 is a wasteful number, since it uses less digits than its factorization.

261299001600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278 (or 250 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

Adding to 261299001600 its reverse (6100992162), we get a palindrome (267399993762).

The spelling of 261299001600 in words is "two hundred sixty-one billion, two hundred ninety-nine million, one thousand, six hundred".