261572198400 has 816 divisors, whose sum is σ = 986220146720. Its totient is φ = 68797071360.

The previous prime is 261572198389. The next prime is 261572198431. The reversal of 261572198400 is 4891275162.

261572198400 is a `hidden beast` number, since 2 + 6 + 1 + 57 + 2 + 198 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3583180764 + ... + 3583180836.

Almost surely, 2^261572198400 is an apocalyptic number.

261572198400 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 261572198400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (493110073360).

261572198400 is an abundant number, since it is smaller than the sum of its proper divisors (724647948320).

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

261572198400 is an frugal number, since it uses more digits than its factorization.

261572198400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136 (or 83 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The spelling of 261572198400 in words is "two hundred sixty-one billion, five hundred seventy-two million, one hundred ninety-eight thousand, four hundred".