261025100 has 72 divisors (see below), whose sum is σ = 658062048. Its totient is φ = 88012800.

The previous prime is 261025087. The next prime is 261025111. The reversal of 261025100 is 1520162.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39644 + ... + 45756.

Almost surely, 2^261025100 is an apocalyptic number.

261025100 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 261025100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (329031024).

261025100 is an abundant number, since it is smaller than the sum of its proper divisors (397036948).

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

261025100 is a wasteful number, since it uses less digits than its factorization.

261025100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6195 (or 6188 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 261025100 is about 16156.2712282259. The cubic root of 261025100 is about 639.0881382600.

Adding to 261025100 its reverse (1520162), we get a palindrome (262545262).

The spelling of 261025100 in words is "two hundred sixty-one million, twenty-five thousand, one hundred".