42721920 has 96 divisors (see below), whose sum is σ = 147544020. Its totient is φ = 11390976.

The previous prime is 42721891. The next prime is 42721927. The reversal of 42721920 is 2912724.

42721920 is a `hidden beast` number, since 427 + 219 + 20 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 42302016 + 419904 = 6504^2 + 648^2 .

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-3 number, since 3×42721920³ (a number of 24 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (42721927) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2052 + ... + 9468.

Almost surely, 2^42721920 is an apocalyptic number.

42721920 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 42721920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73772010).

42721920 is an abundant number, since it is smaller than the sum of its proper divisors (104822100).

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

42721920 is a wasteful number, since it uses less digits than its factorization.

42721920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7442 (or 7427 counting only the distinct ones).

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

The square root of 42721920 is about 6536.2007313117. The cubic root of 42721920 is about 349.5829590564.

The spelling of 42721920 in words is "forty-two million, seven hundred twenty-one thousand, nine hundred twenty".