1217639864 has 24 divisors (see below), whose sum is σ = 2609787960. Its totient is φ = 521733744.

The previous prime is 1217639851. The next prime is 1217639873. The reversal of 1217639864 is 4689367121.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 258797 + ... + 263459.

It is an arithmetic number, because the mean of its divisors is an integer number (108741165).

Almost surely, 2^1217639864 is an apocalyptic number.

1217639864 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1217639864 is an abundant number, since it is smaller than the sum of its proper divisors (1392148096).

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

1217639864 is an frugal number, since it uses more digits than its factorization.

1217639864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9339 (or 4672 counting only the distinct ones).

The product of its digits is 435456, while the sum is 47.

The square root of 1217639864 is about 34894.6967890538. The cubic root of 1217639864 is about 1067.8402483308.

The spelling of 1217639864 in words is "one billion, two hundred seventeen million, six hundred thirty-nine thousand, eight hundred sixty-four".