20661266472 has 256 divisors, whose sum is σ = 68379033600. Its totient is φ = 5036666880.

The previous prime is 20661266471. The next prime is 20661266473. The reversal of 20661266472 is 27466216602.

It is an interprime number because it is at equal distance from previous prime (20661266471) and next prime (20661266473).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (20661266471) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 15047578 + ... + 15048950.

It is an arithmetic number, because the mean of its divisors is an integer number (267105600).

Almost surely, 2^20661266472 is an apocalyptic number.

20661266472 is a gapful number since it is divisible by the number (22) 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 20661266472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34189516800).

20661266472 is an abundant number, since it is smaller than the sum of its proper divisors (47717767128).

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

20661266472 is a wasteful number, since it uses less digits than its factorization.

20661266472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1896 (or 1892 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 42.

The spelling of 20661266472 in words is "twenty billion, six hundred sixty-one million, two hundred sixty-six thousand, four hundred seventy-two".