1261106100 has 108 divisors (see below), whose sum is σ = 4124798496. Its totient is φ = 321668160.

The previous prime is 1261106083. The next prime is 1261106117. The reversal of 1261106100 is 16011621.

It is an interprime number because it is at equal distance from previous prime (1261106083) and next prime (1261106117).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

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 35 ways as a sum of consecutive naturals, for example, 9762 + ... + 51161.

Almost surely, 2^1261106100 is an apocalyptic number.

1261106100 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 1261106100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2062399248).

1261106100 is an abundant number, since it is smaller than the sum of its proper divisors (2863692396).

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

1261106100 is a wasteful number, since it uses less digits than its factorization.

1261106100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60966 (or 60956 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 1261106100 is about 35512.0556994382. The cubic root of 1261106100 is about 1080.3982584708.

Adding to 1261106100 its reverse (16011621), we get a palindrome (1277117721).

The spelling of 1261106100 in words is "one billion, two hundred sixty-one million, one hundred six thousand, one hundred".