20661073500 has 96 divisors (see below), whose sum is σ = 60285476160. Its totient is φ = 5498592000.

The previous prime is 20661073493. The next prime is 20661073513. The reversal of 20661073500 is 537016602.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 749970 + ... + 777030.

It is an arithmetic number, because the mean of its divisors is an integer number (627973710).

Almost surely, 2^20661073500 is an apocalyptic number.

20661073500 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 20661073500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30142738080).

20661073500 is an abundant number, since it is smaller than the sum of its proper divisors (39624402660).

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

20661073500 is a wasteful number, since it uses less digits than its factorization.

20661073500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27592 (or 27580 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 30.

The spelling of 20661073500 in words is "twenty billion, six hundred sixty-one million, seventy-three thousand, five hundred".