84308721 has 32 divisors (see below), whose sum is σ = 131788800. Its totient is φ = 46949760.

The previous prime is 84308671. The next prime is 84308723. The reversal of 84308721 is 12780348.

It is not a de Polignac number, because 84308721 - 2⁹ = 84308209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (84308723) 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 31 ways as a sum of consecutive naturals, for example, 147366 + ... + 147936.

It is an arithmetic number, because the mean of its divisors is an integer number (4118400).

Almost surely, 2^84308721 is an apocalyptic number.

It is an amenable number.

84308721 is a deficient number, since it is larger than the sum of its proper divisors (47480079).

84308721 is a wasteful number, since it uses less digits than its factorization.

84308721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 749.

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 84308721 is about 9181.9780548638. The cubic root of 84308721 is about 438.4877856272.

The spelling of 84308721 in words is "eighty-four million, three hundred eight thousand, seven hundred twenty-one".