42721987 has 16 divisors (see below), whose sum is σ = 53482752. Its totient is φ = 33153120.

The previous prime is 42721981. The next prime is 42722027. The reversal of 42721987 is 78912724.

42721987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 42721987 - 2⁷ = 42721859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42721981) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 20328 + ... + 22330.

It is an arithmetic number, because the mean of its divisors is an integer number (3342672).

Almost surely, 2^42721987 is an apocalyptic number.

42721987 is a deficient number, since it is larger than the sum of its proper divisors (10760765).

42721987 is a wasteful number, since it uses less digits than its factorization.

42721987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2298.

The product of its digits is 56448, while the sum is 40.

The square root of 42721987 is about 6536.2058566113. The cubic root of 42721987 is about 349.5831418045.

The spelling of 42721987 in words is "forty-two million, seven hundred twenty-one thousand, nine hundred eighty-seven".