84071721 has 16 divisors (see below), whose sum is σ = 117186560. Its totient is φ = 53548560.

The previous prime is 84071711. The next prime is 84071723. The reversal of 84071721 is 12717048.

It is not a de Polignac number, because 84071721 - 2¹⁸ = 83809577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (84071723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1626 + ... + 13068.

It is an arithmetic number, because the mean of its divisors is an integer number (7324160).

Almost surely, 2^84071721 is an apocalyptic number.

It is an amenable number.

84071721 is a deficient number, since it is larger than the sum of its proper divisors (33114839).

84071721 is a wasteful number, since it uses less digits than its factorization.

84071721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11556.

The product of its (nonzero) digits is 3136, while the sum is 30.

The square root of 84071721 is about 9169.0632564074. The cubic root of 84071721 is about 438.0765227739.

Adding to 84071721 its reverse (12717048), we get a palindrome (96788769).

The spelling of 84071721 in words is "eighty-four million, seventy-one thousand, seven hundred twenty-one".