1217664656 has 40 divisors (see below), whose sum is σ = 2583792960. Its totient is φ = 552468096.

The previous prime is 1217664629. The next prime is 1217664691. The reversal of 1217664656 is 6564667121.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37340 + ... + 61883.

It is an arithmetic number, because the mean of its divisors is an integer number (64594824).

Almost surely, 2^1217664656 is an apocalyptic number.

1217664656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1217664656 is an abundant number, since it is smaller than the sum of its proper divisors (1366128304).

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

1217664656 is a wasteful number, since it uses less digits than its factorization.

1217664656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99303 (or 99297 counting only the distinct ones).

The product of its digits is 362880, while the sum is 44.

The square root of 1217664656 is about 34895.0520274723. The cubic root of 1217664656 is about 1067.8474956066.

The spelling of 1217664656 in words is "one billion, two hundred seventeen million, six hundred sixty-four thousand, six hundred fifty-six".