1211993280 has 560 divisors, whose sum is σ = 4779751680. Its totient is φ = 290138112.

The previous prime is 1211993213. The next prime is 1211993297. The reversal of 1211993280 is 823991121.

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

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 11326987 + ... + 11327093.

Almost surely, 2^1211993280 is an apocalyptic number.

1211993280 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 1211993280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2389875840).

1211993280 is an abundant number, since it is smaller than the sum of its proper divisors (3567758400).

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

1211993280 is a wasteful number, since it uses less digits than its factorization.

1211993280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178 (or 159 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 1211993280 is about 34813.6938574464. The cubic root of 1211993280 is about 1066.1870517399.

The spelling of 1211993280 in words is "one billion, two hundred eleven million, nine hundred ninety-three thousand, two hundred eighty".