4020721920 has 216 divisors, whose sum is σ = 14288774136. Its totient is φ = 1043103744.

The previous prime is 4020721919. The next prime is 4020721921. The reversal of 4020721920 is 291270204.

4020721920 is a `hidden beast` number, since 402 + 0 + 72 + 192 + 0 = 666.

4020721920 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (4020721919) and next prime (4020721921).

It can be written as a sum of positive squares in 4 ways, for example, as 1470875904 + 2549846016 = 38352^2 + 50496^2 .

It is not an unprimeable number, because it can be changed into a prime (4020721921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 421524 + ... + 430956.

Almost surely, 2^4020721920 is an apocalyptic number.

4020721920 is a gapful number since it is divisible by the number (40) 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 4020721920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7144387068).

4020721920 is an abundant number, since it is smaller than the sum of its proper divisors (10268052216).

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

4020721920 is a wasteful number, since it uses less digits than its factorization.

4020721920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9497 (or 9480 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 4020721920 is about 63409.1627448273. The cubic root of 4020721920 is about 1590.1374984925.

The spelling of 4020721920 in words is "four billion, twenty million, seven hundred twenty-one thousand, nine hundred twenty".