1216591740 has 432 divisors, whose sum is σ = 4843605312. Its totient is φ = 240648192.

The previous prime is 1216591721. The next prime is 1216591771. The reversal of 1216591740 is 471956121.

1216591740 is a `hidden beast` number, since 1 + 21 + 6 + 591 + 7 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1216591695 and 1216591704.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 4733692 + ... + 4733948.

Almost surely, 2^1216591740 is an apocalyptic number.

1216591740 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 1216591740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2421802656).

1216591740 is an abundant number, since it is smaller than the sum of its proper divisors (3627013572).

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

1216591740 is a wasteful number, since it uses less digits than its factorization.

1216591740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326 (or 304 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 1216591740 is about 34879.6751705058. The cubic root of 1216591740 is about 1067.5337673761.

The spelling of 1216591740 in words is "one billion, two hundred sixteen million, five hundred ninety-one thousand, seven hundred forty".