84731021 has 12 divisors (see below), whose sum is σ = 87406044. Its totient is φ = 82128000.

The previous prime is 84730991. The next prime is 84731039. The reversal of 84731021 is 12013748.

It can be written as a sum of positive squares in 2 ways, for example, as 74200996 + 10530025 = 8614^2 + 3245^2 .

It is not a de Polignac number, because 84731021 - 2¹⁸ = 84468877 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84731921) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 351461 + ... + 351701.

It is an arithmetic number, because the mean of its divisors is an integer number (7283837).

Almost surely, 2^84731021 is an apocalyptic number.

It is an amenable number.

84731021 is a deficient number, since it is larger than the sum of its proper divisors (2675023).

84731021 is a wasteful number, since it uses less digits than its factorization.

84731021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 460 (or 401 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 84731021 is about 9204.9454642600. The cubic root of 84731021 is about 439.2186909281.

Adding to 84731021 its reverse (12013748), we get a palindrome (96744769).

The spelling of 84731021 in words is "eighty-four million, seven hundred thirty-one thousand, twenty-one".