18649713978 has 96 divisors (see below), whose sum is σ = 46624241664. Its totient is φ = 5277501216.

The previous prime is 18649713977. The next prime is 18649714073. The reversal of 18649713978 is 87931794681.

18649713978 is a `hidden beast` number, since 1 + 8 + 6 + 497 + 139 + 7 + 8 = 666.

It is a super-2 number, since 2×18649713978² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (18649713977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6458451 + ... + 6461337.

It is an arithmetic number, because the mean of its divisors is an integer number (485669184).

Almost surely, 2^18649713978 is an apocalyptic number.

18649713978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18649713978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23312120832).

18649713978 is an abundant number, since it is smaller than the sum of its proper divisors (27974527686).

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

18649713978 is a wasteful number, since it uses less digits than its factorization.

18649713978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3376 (or 3373 counting only the distinct ones).

The product of its digits is 18289152, while the sum is 63.

The spelling of 18649713978 in words is "eighteen billion, six hundred forty-nine million, seven hundred thirteen thousand, nine hundred seventy-eight".