261431400 has 96 divisors (see below), whose sum is σ = 829366560. Its totient is φ = 68087040.

The previous prime is 261431399. The next prime is 261431453. The reversal of 261431400 is 4134162.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20734 + ... + 30866.

It is an arithmetic number, because the mean of its divisors is an integer number (8639235).

Almost surely, 2^261431400 is an apocalyptic number.

261431400 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 261431400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (414683280).

261431400 is an abundant number, since it is smaller than the sum of its proper divisors (567935160).

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

261431400 is a wasteful number, since it uses less digits than its factorization.

261431400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10195 (or 10186 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 261431400 is about 16168.8404036901. The cubic root of 261431400 is about 639.4195583688.

Adding to 261431400 its reverse (4134162), we get a palindrome (265565562).

The spelling of 261431400 in words is "two hundred sixty-one million, four hundred thirty-one thousand, four hundred".