84171021 has 32 divisors (see below), whose sum is σ = 127509120. Its totient is φ = 48921600.

The previous prime is 84170987. The next prime is 84171023. The reversal of 84171021 is 12017148.

It is not a de Polignac number, because 84171021 - 2⁹ = 84170509 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 84170982 and 84171000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84171023) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 268761 + ... + 269073.

It is an arithmetic number, because the mean of its divisors is an integer number (3984660).

Almost surely, 2^84171021 is an apocalyptic number.

It is an amenable number.

84171021 is a deficient number, since it is larger than the sum of its proper divisors (43338099).

84171021 is a wasteful number, since it uses less digits than its factorization.

84171021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 637.

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 84171021 is about 9174.4766063247. The cubic root of 84171021 is about 438.2489306600.

Adding to 84171021 its reverse (12017148), we get a palindrome (96188169).

The spelling of 84171021 in words is "eighty-four million, one hundred seventy-one thousand, twenty-one".