1261745100 has 810 divisors, whose sum is σ = 5513654916. Its totient is φ = 246758400.

The previous prime is 1261745099. The next prime is 1261745119. The reversal of 1261745100 is 15471621.

It is a happy number.

1261745100 is a `hidden beast` number, since 1 + 2 + 617 + 45 + 1 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (810).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 269 ways as a sum of consecutive naturals, for example, 74220292 + ... + 74220308.

Almost surely, 2^1261745100 is an apocalyptic number.

1261745100 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 1261745100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2756827458).

1261745100 is an abundant number, since it is smaller than the sum of its proper divisors (4251909816).

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

1261745100 is a wasteful number, since it uses less digits than its factorization.

1261745100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85 (or 45 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 1261745100 is about 35521.0515047063. The cubic root of 1261745100 is about 1080.5807062221.

The spelling of 1261745100 in words is "one billion, two hundred sixty-one million, seven hundred forty-five thousand, one hundred".