649123843 has 4 divisors (see below), whose sum is σ = 649275480. Its totient is φ = 648972208.

The previous prime is 649123831. The next prime is 649123877. The reversal of 649123843 is 348321946.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 649123843 - 2⁹ = 649123331 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 649123796 and 649123805.

It is not an unprimeable number, because it can be changed into a prime (649423843) 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, 69205 + ... + 78022.

It is an arithmetic number, because the mean of its divisors is an integer number (162318870).

Almost surely, 2^649123843 is an apocalyptic number.

649123843 is a deficient number, since it is larger than the sum of its proper divisors (151637).

649123843 is a wasteful number, since it uses less digits than its factorization.

649123843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151636.

The product of its digits is 124416, while the sum is 40.

The square root of 649123843 is about 25477.9089212596. The cubic root of 649123843 is about 865.8497193299.

The spelling of 649123843 in words is "six hundred forty-nine million, one hundred twenty-three thousand, eight hundred forty-three".