1216643000 has 64 divisors (see below), whose sum is σ = 2853321120. Its totient is φ = 485568000.

The previous prime is 1216642993. The next prime is 1216643011. The reversal of 1216643000 is 3466121.

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, 561920 + ... + 564080.

Almost surely, 2^1216643000 is an apocalyptic number.

1216643000 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 1216643000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1426660560).

1216643000 is an abundant number, since it is smaller than the sum of its proper divisors (1636678120).

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

1216643000 is a wasteful number, since it uses less digits than its factorization.

1216643000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2745 (or 2731 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 1216643000 is about 34880.4099746548. The cubic root of 1216643000 is about 1067.5487603576.

The spelling of 1216643000 in words is "one billion, two hundred sixteen million, six hundred forty-three thousand".