1216881940 has 24 divisors (see below), whose sum is σ = 2614883040. Its totient is φ = 475432608.

The previous prime is 1216881931. The next prime is 1216881949. The reversal of 1216881940 is 491886121.

It is an interprime number because it is at equal distance from previous prime (1216881931) and next prime (1216881949).

It is a junction number, because it is equal to n+sod(n) for n = 1216881893 and 1216881902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216881949) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 706630 + ... + 708349.

It is an arithmetic number, because the mean of its divisors is an integer number (108953460).

Almost surely, 2^1216881940 is an apocalyptic number.

1216881940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1216881940 is an abundant number, since it is smaller than the sum of its proper divisors (1398001100).

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

1216881940 is a wasteful number, since it uses less digits than its factorization.

1216881940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1415031 (or 1415029 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 40.

The square root of 1216881940 is about 34883.8349382633. The cubic root of 1216881940 is about 1067.6186421016.

The spelling of 1216881940 in words is "one billion, two hundred sixteen million, eight hundred eighty-one thousand, nine hundred forty".