1261335400 has 96 divisors (see below), whose sum is σ = 3344082840. Its totient is φ = 438312960.

The previous prime is 1261335379. The next prime is 1261335401. The reversal of 1261335400 is 45331621.

It can be written as a sum of positive squares in 12 ways, for example, as 91204 + 1261244196 = 302^2 + 35514^2 .

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

It is not an unprimeable number, because it can be changed into a prime (1261335401) 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, 29932 + ... + 58468.

Almost surely, 2^1261335400 is an apocalyptic number.

1261335400 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 1261335400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1672041420).

1261335400 is an abundant number, since it is smaller than the sum of its proper divisors (2082747440).

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

1261335400 is a wasteful number, since it uses less digits than its factorization.

1261335400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28583 (or 28574 counting only the distinct ones).

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

The square root of 1261335400 is about 35515.2840337790. The cubic root of 1261335400 is about 1080.4637354642.

The spelling of 1261335400 in words is "one billion, two hundred sixty-one million, three hundred thirty-five thousand, four hundred".