1216261240 has 64 divisors (see below), whose sum is σ = 2801304000. Its totient is φ = 475130880.

The previous prime is 1216261219. The next prime is 1216261271. The reversal of 1216261240 is 421626121.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 307596 + ... + 311524.

It is an arithmetic number, because the mean of its divisors is an integer number (43770375).

Almost surely, 2^1216261240 is an apocalyptic number.

1216261240 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 1216261240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1400652000).

1216261240 is an abundant number, since it is smaller than the sum of its proper divisors (1585042760).

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

1216261240 is a wasteful number, since it uses less digits than its factorization.

1216261240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4120 (or 4116 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 1216261240 is about 34874.9371325598. The cubic root of 1216261240 is about 1067.4370896787.

Adding to 1216261240 its reverse (421626121), we get a palindrome (1637887361).

The spelling of 1216261240 in words is "one billion, two hundred sixteen million, two hundred sixty-one thousand, two hundred forty".