21660365364040 has 128 divisors (see below), whose sum is σ = 52816274784000. Its totient is φ = 7947170288640.

The previous prime is 21660365364019. The next prime is 21660365364047. The reversal of 21660365364040 is 4046356306612.

It is not an unprimeable number, because it can be changed into a prime (21660365364047) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 544224061 + ... + 544263859.

It is an arithmetic number, because the mean of its divisors is an integer number (412627146750).

Almost surely, 2^{21660365364040} is an apocalyptic number.

21660365364040 is a gapful number since it is divisible by the number (20) 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 21660365364040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26408137392000).

21660365364040 is an abundant number, since it is smaller than the sum of its proper divisors (31155909419960).

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

21660365364040 is a wasteful number, since it uses less digits than its factorization.

21660365364040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46407 (or 46403 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 46.

The spelling of 21660365364040 in words is "twenty-one trillion, six hundred sixty billion, three hundred sixty-five million, three hundred sixty-four thousand, forty".