84661021 has 2 divisors, whose sum is σ = 84661022. Its totient is φ = 84661020.

The previous prime is 84661013. The next prime is 84661033. The reversal of 84661021 is 12016648.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80192025 + 4468996 = 8955^2 + 2114^2 .

It is a cyclic number.

It is not a de Polignac number, because 84661021 - 2³ = 84661013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84661051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42330510 + 42330511.

It is an arithmetic number, because the mean of its divisors is an integer number (42330511).

Almost surely, 2^84661021 is an apocalyptic number.

It is an amenable number.

84661021 is a deficient number, since it is larger than the sum of its proper divisors (1).

84661021 is an equidigital number, since it uses as much as digits as its factorization.

84661021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 84661021 is about 9201.1423747272. The cubic root of 84661021 is about 439.0977050185.

Adding to 84661021 its reverse (12016648), we get a palindrome (96677669).

The spelling of 84661021 in words is "eighty-four million, six hundred sixty-one thousand, twenty-one".