83725821 has 6 divisors (see below), whose sum is σ = 120937310. Its totient is φ = 55817208.

The previous prime is 83725801. The next prime is 83725853. The reversal of 83725821 is 12852738.

83725821 is a `hidden beast` number, since 8 + 3 + 72 + 582 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 59074596 + 24651225 = 7686^2 + 4965^2 .

It is not a de Polignac number, because 83725821 - 2⁶ = 83725757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (83725801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4651426 + ... + 4651443.

Almost surely, 2^83725821 is an apocalyptic number.

It is an amenable number.

83725821 is a deficient number, since it is larger than the sum of its proper divisors (37211489).

83725821 is a wasteful number, since it uses less digits than its factorization.

83725821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9302875 (or 9302872 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 83725821 is about 9150.1814736102. The cubic root of 83725821 is about 437.4748977162.

It can be divided in two parts, 83 and 725821, that added together give a square (725904 = 852²).

The spelling of 83725821 in words is "eighty-three million, seven hundred twenty-five thousand, eight hundred twenty-one".