84561021 has 12 divisors (see below), whose sum is σ = 125445372. Its totient is φ = 54850176.

The previous prime is 84561007. The next prime is 84561031. The reversal of 84561021 is 12016548.

84561021 is a `hidden beast` number, since 8 + 45 + 610 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 75012921 + 9548100 = 8661^2 + 3090^2 .

It is not a de Polignac number, because 84561021 - 2⁵ = 84560989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84561031) 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 11 ways as a sum of consecutive naturals, for example, 126636 + ... + 127301.

It is an arithmetic number, because the mean of its divisors is an integer number (10453781).

Almost surely, 2^84561021 is an apocalyptic number.

It is an amenable number.

84561021 is a deficient number, since it is larger than the sum of its proper divisors (40884351).

84561021 is a wasteful number, since it uses less digits than its factorization.

84561021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253980 (or 253977 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 84561021 is about 9195.7066612632. The cubic root of 84561021 is about 438.9247522641.

Adding to 84561021 its reverse (12016548), we get a palindrome (96577569).

The spelling of 84561021 in words is "eighty-four million, five hundred sixty-one thousand, twenty-one".