84720869 has 2 divisors, whose sum is σ = 84720870. Its totient is φ = 84720868.

The previous prime is 84720863. The next prime is 84720913. The reversal of 84720869 is 96802748.

It is an a-pointer prime, because the next prime (84720913) can be obtained adding 84720869 to its sum of digits (44).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64802500 + 19918369 = 8050^2 + 4463^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-84720869 is a prime.

It is a super-2 number, since 2×84720869² = 14355251288230322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84720863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42360434 + 42360435.

It is an arithmetic number, because the mean of its divisors is an integer number (42360435).

Almost surely, 2^84720869 is an apocalyptic number.

It is an amenable number.

84720869 is a deficient number, since it is larger than the sum of its proper divisors (1).

84720869 is an equidigital number, since it uses as much as digits as its factorization.

84720869 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 193536, while the sum is 44.

The square root of 84720869 is about 9204.3940050391. The cubic root of 84720869 is about 439.2011486467.

The spelling of 84720869 in words is "eighty-four million, seven hundred twenty thousand, eight hundred sixty-nine".