261231032500 has 180 divisors, whose sum is σ = 594120320640. Its totient is φ = 100466040000.

The previous prime is 261231032443. The next prime is 261231032581. The reversal of 261231032500 is 5230132162.

261231032500 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 545367261 + ... + 545367739.

It is an arithmetic number, because the mean of its divisors is an integer number (3300668448).

Almost surely, 2^261231032500 is an apocalyptic number.

261231032500 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 261231032500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (297060160320).

261231032500 is an abundant number, since it is smaller than the sum of its proper divisors (332889288140).

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

261231032500 is a wasteful number, since it uses less digits than its factorization.

261231032500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 792 (or 744 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

Adding to 261231032500 its reverse (5230132162), we get a palindrome (266461164662).

The spelling of 261231032500 in words is "two hundred sixty-one billion, two hundred thirty-one million, thirty-two thousand, five hundred".