20929720 has 64 divisors (see below), whose sum is σ = 56998080. Its totient is φ = 6752256.

The previous prime is 20929693. The next prime is 20929729. The reversal of 20929720 is 2792902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20929729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2562 + ... + 6958.

It is an arithmetic number, because the mean of its divisors is an integer number (890595).

Almost surely, 2^20929720 is an apocalyptic number.

20929720 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 20929720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28499040).

20929720 is an abundant number, since it is smaller than the sum of its proper divisors (36068360).

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

20929720 is a wasteful number, since it uses less digits than its factorization.

20929720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4432 (or 4428 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 20929720 is about 4574.9010918270. The cubic root of 20929720 is about 275.5843003409.

It can be divided in two parts, 209 and 29720, that added together give a square (29929 = 173²).

The spelling of 20929720 in words is "twenty million, nine hundred twenty-nine thousand, seven hundred twenty".