261401400 has 144 divisors (see below), whose sum is σ = 945486360. Its totient is φ = 64339200.

The previous prime is 261401383. The next prime is 261401407. The reversal of 261401400 is 4104162.

261401400 is a `hidden beast` number, since 261 + 4 + 0 + 1 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261401407) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 17815 + ... + 28985.

Almost surely, 2^261401400 is an apocalyptic number.

261401400 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 261401400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (472743180).

261401400 is an abundant number, since it is smaller than the sum of its proper divisors (684084960).

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

261401400 is a wasteful number, since it uses less digits than its factorization.

261401400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11206 (or 11194 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 261401400 is about 16167.9126667607. The cubic root of 261401400 is about 639.3950990262.

Adding to 261401400 its reverse (4104162), we get a palindrome (265505562).

The spelling of 261401400 in words is "two hundred sixty-one million, four hundred one thousand, four hundred".