1216217340 has 144 divisors (see below), whose sum is σ = 3988272288. Its totient is φ = 298225152.

The previous prime is 1216217309. The next prime is 1216217347. The reversal of 1216217340 is 437126121.

1216217340 is a `hidden beast` number, since 1 + 2 + 1 + 621 + 7 + 34 + 0 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216217347) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 717534 + ... + 719226.

Almost surely, 2^1216217340 is an apocalyptic number.

1216217340 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 1216217340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1994136144).

1216217340 is an abundant number, since it is smaller than the sum of its proper divisors (2772054948).

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

1216217340 is a wasteful number, since it uses less digits than its factorization.

1216217340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2028 (or 2023 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 1216217340 is about 34874.3077350648. The cubic root of 1216217340 is about 1067.4242467547.

The spelling of 1216217340 in words is "one billion, two hundred sixteen million, two hundred seventeen thousand, three hundred forty".