1216735380 has 144 divisors (see below), whose sum is σ = 4332182400. Its totient is φ = 270584064.

The previous prime is 1216735379. The next prime is 1216735411. The reversal of 1216735380 is 835376121.

1216735380 = 2472² + 2473² + ... + 2656².

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 33571 + ... + 59669.

It is an arithmetic number, because the mean of its divisors is an integer number (30084600).

Almost surely, 2^1216735380 is an apocalyptic number.

1216735380 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 1216735380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2166091200).

1216735380 is an abundant number, since it is smaller than the sum of its proper divisors (3115447020).

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

1216735380 is a wasteful number, since it uses less digits than its factorization.

1216735380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26158 (or 26153 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 1216735380 is about 34881.7341885406. The cubic root of 1216735380 is about 1067.5757794197.

The spelling of 1216735380 in words is "one billion, two hundred sixteen million, seven hundred thirty-five thousand, three hundred eighty".