18061021440 has 864 divisors, whose sum is σ = 80642177280. Its totient is φ = 3746856960.

The previous prime is 18061021411. The next prime is 18061021471. The reversal of 18061021440 is 4412016081.

It is a happy number.

18061021440 is a `hidden beast` number, since 1 + 8 + 0 + 610 + 2 + 1 + 4 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a super-2 number, since 2×18061021440² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 29272012 + ... + 29272628.

Almost surely, 2^18061021440 is an apocalyptic number.

18061021440 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 18061021440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40321088640).

18061021440 is an abundant number, since it is smaller than the sum of its proper divisors (62581155840).

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

18061021440 is a wasteful number, since it uses less digits than its factorization.

18061021440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 676 (or 645 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The spelling of 18061021440 in words is "eighteen billion, sixty-one million, twenty-one thousand, four hundred forty".