1216505040 has 120 divisors (see below), whose sum is σ = 4006276320. Its totient is φ = 305301504.

The previous prime is 1216505009. The next prime is 1216505107. The reversal of 1216505040 is 405056121.

It is a tau number, because it is divible by the number of its divisors (120).

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 1216505040.

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, 60591 + ... + 78129.

It is an arithmetic number, because the mean of its divisors is an integer number (33385636).

Almost surely, 2^1216505040 is an apocalyptic number.

1216505040 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 1216505040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2003138160).

1216505040 is an abundant number, since it is smaller than the sum of its proper divisors (2789771280).

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

1216505040 is a wasteful number, since it uses less digits than its factorization.

1216505040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17589 (or 17566 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 1216505040 is about 34878.4323042192. The cubic root of 1216505040 is about 1067.5084076290.

The spelling of 1216505040 in words is "one billion, two hundred sixteen million, five hundred five thousand, forty".