261998400 has 84 divisors (see below), whose sum is σ = 859588832. Its totient is φ = 69864960.

The previous prime is 261998311. The next prime is 261998411. The reversal of 261998400 is 4899162.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22492 + ... + 32091.

Almost surely, 2^261998400 is an apocalyptic number.

261998400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261998400 is an abundant number, since it is smaller than the sum of its proper divisors (597590432).

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

261998400 is a wasteful number, since it uses less digits than its factorization.

261998400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54608 (or 54593 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 261998400 is about 16186.3646319981. The cubic root of 261998400 is about 639.8814884727.

The spelling of 261998400 in words is "two hundred sixty-one million, nine hundred ninety-eight thousand, four hundred".