20729880 has 96 divisors (see below), whose sum is σ = 68234400. Its totient is φ = 5457408.

The previous prime is 20729873. The next prime is 20729897. The reversal of 20729880 is 8892702.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31717 + ... + 32363.

It is an arithmetic number, because the mean of its divisors is an integer number (710775).

Almost surely, 2^20729880 is an apocalyptic number.

20729880 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 20729880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34117200).

20729880 is an abundant number, since it is smaller than the sum of its proper divisors (47504520).

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

20729880 is a wasteful number, since it uses less digits than its factorization.

20729880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 753 (or 746 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 20729880 is about 4553.0077970502. The cubic root of 20729880 is about 274.7043875782.

It can be divided in two parts, 20729 and 880, that added together give a square (21609 = 147²).

The spelling of 20729880 in words is "twenty million, seven hundred twenty-nine thousand, eight hundred eighty".