1261242240 has 192 divisors, whose sum is σ = 4272482160. Its totient is φ = 316407808.

The previous prime is 1261242239. The next prime is 1261242251. The reversal of 1261242240 is 422421621.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 1261242240.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 553744 + ... + 556016.

Almost surely, 2^1261242240 is an apocalyptic number.

1261242240 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 1261242240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2136241080).

1261242240 is an abundant number, since it is smaller than the sum of its proper divisors (3011239920).

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

1261242240 is a wasteful number, since it uses less digits than its factorization.

1261242240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2329 (or 2300 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 1261242240 is about 35513.9724615538. The cubic root of 1261242240 is about 1080.4371344296.

Adding to 1261242240 its reverse (422421621), we get a palindrome (1683663861).

The spelling of 1261242240 in words is "one billion, two hundred sixty-one million, two hundred forty-two thousand, two hundred forty".