20929680 has 120 divisors (see below), whose sum is σ = 72104760. Its totient is φ = 5437440.

The previous prime is 20929673. The next prime is 20929693. The reversal of 20929680 is 8692902.

It can be written as a sum of positive squares in 4 ways, for example, as 571536 + 20358144 = 756^2 + 4512^2 .

It is a tau number, because it is divible by the number of its divisors (120).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29166 + ... + 29874.

It is an arithmetic number, because the mean of its divisors is an integer number (600873).

Almost surely, 2^20929680 is an apocalyptic number.

20929680 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 20929680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36052380).

20929680 is an abundant number, since it is smaller than the sum of its proper divisors (51175080).

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

20929680 is a wasteful number, since it uses less digits than its factorization.

20929680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769 (or 760 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 20929680 is about 4574.8967201457. The cubic root of 20929680 is about 275.5841247790.

It can be divided in two parts, 20929 and 680, that added together give a square (21609 = 147²).

The spelling of 20929680 in words is "twenty million, nine hundred twenty-nine thousand, six hundred eighty".