18266217840 has 240 divisors, whose sum is σ = 66361565088. Its totient is φ = 4475971584.

The previous prime is 18266217833. The next prime is 18266217841. The reversal of 18266217840 is 4871266281.

18266217840 is a `hidden beast` number, since 18 + 2 + 6 + 621 + 7 + 8 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18266217841) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2120422 + ... + 2129018.

Almost surely, 2^18266217840 is an apocalyptic number.

18266217840 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 18266217840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33180782544).

18266217840 is an abundant number, since it is smaller than the sum of its proper divisors (48095347248).

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

18266217840 is a wasteful number, since it uses less digits than its factorization.

18266217840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8856 (or 8847 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The spelling of 18266217840 in words is "eighteen billion, two hundred sixty-six million, two hundred seventeen thousand, eight hundred forty".