864551 has 2 divisors, whose sum is σ = 864552. Its totient is φ = 864550.

The previous prime is 864541. The next prime is 864581. The reversal of 864551 is 155468.

It is a happy number.

864551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-864551 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (864511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432275 + 432276.

It is an arithmetic number, because the mean of its divisors is an integer number (432276).

2⁸⁶⁴⁵⁵¹ is an apocalyptic number.

864551 is a deficient number, since it is larger than the sum of its proper divisors (1).

864551 is an equidigital number, since it uses as much as digits as its factorization.

864551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4800, while the sum is 29.

The square root of 864551 is about 929.8123466593. The cubic root of 864551 is about 95.2643055281.

The spelling of 864551 in words is "eight hundred sixty-four thousand, five hundred fifty-one".