649723 has 4 divisors (see below), whose sum is σ = 687960. Its totient is φ = 611488.

The previous prime is 649717. The next prime is 649739. The reversal of 649723 is 327946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 327946 = 2 ⋅163973.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649723 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a d-powerful number, because it can be written as 6² + 4 + 7⁶ + 9² + 2⁹ + 3¹² .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649783) 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, 19093 + ... + 19126.

It is an arithmetic number, because the mean of its divisors is an integer number (171990).

2⁶⁴⁹⁷²³ is an apocalyptic number.

649723 is a deficient number, since it is larger than the sum of its proper divisors (38237).

649723 is a wasteful number, since it uses less digits than its factorization.

649723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38236.

The product of its digits is 9072, while the sum is 31.

The square root of 649723 is about 806.0539684165. The cubic root of 649723 is about 86.6116037482.

It can be divided in two parts, 6 and 49723, that added together give a square (49729 = 223²).

The spelling of 649723 in words is "six hundred forty-nine thousand, seven hundred twenty-three".