261490900 has 72 divisors (see below), whose sum is σ = 626209920. Its totient is φ = 93984000.

The previous prime is 261490871. The next prime is 261490903. The reversal of 261490900 is 9094162.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261490903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 96565 + ... + 99235.

It is an arithmetic number, because the mean of its divisors is an integer number (8697360).

Almost surely, 2^261490900 is an apocalyptic number.

261490900 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 261490900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (313104960).

261490900 is an abundant number, since it is smaller than the sum of its proper divisors (364719020).

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

261490900 is a wasteful number, since it uses less digits than its factorization.

261490900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2785 (or 2778 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 261490900 is about 16170.6802577999. The cubic root of 261490900 is about 639.4680638630.

The spelling of 261490900 in words is "two hundred sixty-one million, four hundred ninety thousand, nine hundred".