1261152100 has 72 divisors (see below), whose sum is σ = 3075428160. Its totient is φ = 445399680.

The previous prime is 1261152097. The next prime is 1261152107. The reversal of 1261152100 is 12511621.

It is not an unprimeable number, because it can be changed into a prime (1261152107) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8811 + ... + 50989.

It is an arithmetic number, because the mean of its divisors is an integer number (42714280).

Almost surely, 2^1261152100 is an apocalyptic number.

1261152100 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 1261152100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1537714080).

1261152100 is an abundant number, since it is smaller than the sum of its proper divisors (1814276060).

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

1261152100 is a wasteful number, since it uses less digits than its factorization.

1261152100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42229 (or 42222 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 19.

The square root of 1261152100 is about 35512.7033609102. The cubic root of 1261152100 is about 1080.4113944831.

Adding to 1261152100 its reverse (12511621), we get a palindrome (1273663721).

The spelling of 1261152100 in words is "one billion, two hundred sixty-one million, one hundred fifty-two thousand, one hundred".