649999 has 4 divisors (see below), whose sum is σ = 742864. Its totient is φ = 557136.

The previous prime is 649991. The next prime is 650011. The reversal of 649999 is 999946.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 999946 = 2 ⋅499973.

It is a cyclic number.

It is not a de Polignac number, because 649999 - 2³ = 649991 is a prime.

It is a Duffinian number.

649999 is a modest number, since divided by 999 gives 649 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46422 + ... + 46435.

It is an arithmetic number, because the mean of its divisors is an integer number (185716).

2⁶⁴⁹⁹⁹⁹ is an apocalyptic number.

649999 is a deficient number, since it is larger than the sum of its proper divisors (92865).

649999 is an equidigital number, since it uses as much as digits as its factorization.

649999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92864.

The product of its digits is 157464, while the sum is 46.

The square root of 649999 is about 806.2251546559. The cubic root of 649999 is about 86.6238661115.

It can be divided in two parts, 64 and 9999, that multiplied together give a palindrome (639936).

The spelling of 649999 in words is "six hundred forty-nine thousand, nine hundred ninety-nine".