20189405664 has 72 divisors (see below), whose sum is σ = 57496099752. Its totient is φ = 6720134400.

The previous prime is 20189405659. The next prime is 20189405669. The reversal of 20189405664 is 46650498102.

20189405664 is a `hidden beast` number, since 2 + 0 + 1 + 89 + 4 + 0 + 566 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (20189405659) and next prime (20189405669).

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×20189405664² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20189405669) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 151887 + ... + 251889.

It is an arithmetic number, because the mean of its divisors is an integer number (798556941).

Almost surely, 2^20189405664 is an apocalyptic number.

20189405664 is a gapful number since it is divisible by the number (24) 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 20189405664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28748049876).

20189405664 is an abundant number, since it is smaller than the sum of its proper divisors (37306694088).

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

20189405664 is a wasteful number, since it uses less digits than its factorization.

20189405664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100720 (or 100709 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 45.

The spelling of 20189405664 in words is "twenty billion, one hundred eighty-nine million, four hundred five thousand, six hundred sixty-four".