84805721 has 60 divisors (see below), whose sum is σ = 123019920. Its totient is φ = 57788640.

The previous prime is 84805711. The next prime is 84805727. The reversal of 84805721 is 12750848.

It is not a de Polignac number, because 84805721 - 2¹⁰ = 84804697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (84805727) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 4463450 + ... + 4463468.

It is an arithmetic number, because the mean of its divisors is an integer number (2050332).

Almost surely, 2^84805721 is an apocalyptic number.

It is an amenable number.

84805721 is a deficient number, since it is larger than the sum of its proper divisors (38214199).

84805721 is a wasteful number, since it uses less digits than its factorization.

84805721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84 (or 50 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 84805721 is about 9209.0021717882. The cubic root of 84805721 is about 439.3477267041.

The spelling of 84805721 in words is "eighty-four million, eight hundred five thousand, seven hundred twenty-one".