1217730816 has 81 divisors (see below), whose sum is σ = 3515854251. Its totient is φ = 405351936.

The previous prime is 1217730799. The next prime is 1217730817. The reversal of 1217730816 is 6180377121.

The square root of 1217730816 is 34896.

It is a perfect power (a square), and thus also a powerful number.

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

It is not an unprimeable number, because it can be changed into a prime (1217730817) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1674645 + ... + 1675371.

Almost surely, 2^1217730816 is an apocalyptic number.

1217730816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

1217730816 is the 34896-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1217730816

1217730816 is an abundant number, since it is smaller than the sum of its proper divisors (2298123435).

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

1217730816 is an frugal number, since it uses more digits than its factorization.

1217730816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1476 (or 732 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The cubic root of 1217730816 is about 1067.8668352254.

Multiplying 1217730816 by its sum of digits (36), we get a square (43838309376 = 209376²).

1217730816 divided by its sum of digits (36) gives a square (33825856 = 5816²).

The spelling of 1217730816 in words is "one billion, two hundred seventeen million, seven hundred thirty thousand, eight hundred sixteen".