1216790640 has 320 divisors, whose sum is σ = 4780944000. Its totient is φ = 281788416.

The previous prime is 1216790633. The next prime is 1216790669. The reversal of 1216790640 is 460976121.

1216790640 is a `hidden beast` number, since 1 + 2 + 1 + 6 + 7 + 9 + 0 + 640 = 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 = 1216790595 and 1216790604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 476086 + ... + 478634.

It is an arithmetic number, because the mean of its divisors is an integer number (14940450).

Almost surely, 2^1216790640 is an apocalyptic number.

1216790640 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 1216790640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2390472000).

1216790640 is an abundant number, since it is smaller than the sum of its proper divisors (3564153360).

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

1216790640 is a wasteful number, since it uses less digits than its factorization.

1216790640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2601 (or 2589 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 1216790640 is about 34882.5262846601. The cubic root of 1216790640 is about 1067.5919410671.

The spelling of 1216790640 in words is "one billion, two hundred sixteen million, seven hundred ninety thousand, six hundred forty".