18649556640 has 960 divisors, whose sum is σ = 80220792960. Its totient is φ = 4017807360.

The previous prime is 18649556633. The next prime is 18649556641. The reversal of 18649556640 is 4665594681.

18649556640 is a `hidden beast` number, since 1 + 8 + 6 + 49 + 556 + 6 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (18649556641) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 53744947 + ... + 53745293.

It is an arithmetic number, because the mean of its divisors is an integer number (83563326).

Almost surely, 2^18649556640 is an apocalyptic number.

18649556640 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 18649556640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40110396480).

18649556640 is an abundant number, since it is smaller than the sum of its proper divisors (61571236320).

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

18649556640 is a wasteful number, since it uses less digits than its factorization.

18649556640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427 (or 410 counting only the distinct ones).

The product of its (nonzero) digits is 6220800, while the sum is 54.

The spelling of 18649556640 in words is "eighteen billion, six hundred forty-nine million, five hundred fifty-six thousand, six hundred forty".