21660410640464 has 160 divisors (see below), whose sum is σ = 46869590630400. Its totient is φ = 9649630932480.

The previous prime is 21660410640461. The next prime is 21660410640469. The reversal of 21660410640464 is 46404601406612.

It is a super-2 number, since 2×21660410640464² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21660410640461) 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, 1389994817 + ... + 1390010399.

It is an arithmetic number, because the mean of its divisors is an integer number (292934941440).

Almost surely, 2^{21660410640464} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21660410640464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23434795315200).

21660410640464 is an abundant number, since it is smaller than the sum of its proper divisors (25209179989936).

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

21660410640464 is a wasteful number, since it uses less digits than its factorization.

21660410640464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18953 (or 18947 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 44.

The spelling of 21660410640464 in words is "twenty-one trillion, six hundred sixty billion, four hundred ten million, six hundred forty thousand, four hundred sixty-four".