84436721 has 2 divisors, whose sum is σ = 84436722. Its totient is φ = 84436720.

The previous prime is 84436687. The next prime is 84436747. The reversal of 84436721 is 12763448.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83466496 + 970225 = 9136^2 + 985^2 .

It is a cyclic number.

It is not a de Polignac number, because 84436721 - 2¹⁸ = 84174577 is a prime.

It is not a weakly prime, because it can be changed into another prime (84436421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42218360 + 42218361.

It is an arithmetic number, because the mean of its divisors is an integer number (42218361).

Almost surely, 2^84436721 is an apocalyptic number.

It is an amenable number.

84436721 is a deficient number, since it is larger than the sum of its proper divisors (1).

84436721 is an equidigital number, since it uses as much as digits as its factorization.

84436721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32256, while the sum is 35.

The square root of 84436721 is about 9188.9455869539. The cubic root of 84436721 is about 438.7095818050.

The spelling of 84436721 in words is "eighty-four million, four hundred thirty-six thousand, seven hundred twenty-one".