1261545500 has 48 divisors (see below), whose sum is σ = 2762052384. Its totient is φ = 503366400.

The previous prime is 1261545499. The next prime is 1261545511. The reversal of 1261545500 is 55451621.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 213587 + ... + 219413.

It is an arithmetic number, because the mean of its divisors is an integer number (57542758).

Almost surely, 2^1261545500 is an apocalyptic number.

1261545500 is a gapful number since it is divisible by the number (10) 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 1261545500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1381026192).

1261545500 is an abundant number, since it is smaller than the sum of its proper divisors (1500506884).

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

1261545500 is a wasteful number, since it uses less digits than its factorization.

1261545500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6279 (or 6267 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 29.

The square root of 1261545500 is about 35518.2417920707. The cubic root of 1261545500 is about 1080.5237228997.

The spelling of 1261545500 in words is "one billion, two hundred sixty-one million, five hundred forty-five thousand, five hundred".