1213445664 has 192 divisors, whose sum is σ = 3640412160. Its totient is φ = 393120000.

The previous prime is 1213445657. The next prime is 1213445687. The reversal of 1213445664 is 4665443121.

1213445664 is a `hidden beast` number, since 12 + 134 + 456 + 64 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8035989 + ... + 8036139.

It is an arithmetic number, because the mean of its divisors is an integer number (18960480).

Almost surely, 2^1213445664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1213445664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1820206080).

1213445664 is an abundant number, since it is smaller than the sum of its proper divisors (2426966496).

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

1213445664 is a wasteful number, since it uses less digits than its factorization.

1213445664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372 (or 358 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 1213445664 is about 34834.5469900213. The cubic root of 1213445664 is about 1066.6127677626.

Adding to 1213445664 its reverse (4665443121), we get a palindrome (5878888785).

The spelling of 1213445664 in words is "one billion, two hundred thirteen million, four hundred forty-five thousand, six hundred sixty-four".