649724123 has 4 divisors (see below), whose sum is σ = 655474008. Its totient is φ = 643974240.

The previous prime is 649724113. The next prime is 649724137. The reversal of 649724123 is 321427946.

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 649724123 - 2⁶ = 649724059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649724113) 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, 2874773 + ... + 2874998.

It is an arithmetic number, because the mean of its divisors is an integer number (163868502).

Almost surely, 2^649724123 is an apocalyptic number.

649724123 is a deficient number, since it is larger than the sum of its proper divisors (5749885).

649724123 is a wasteful number, since it uses less digits than its factorization.

649724123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5749884.

The product of its digits is 72576, while the sum is 38.

The square root of 649724123 is about 25489.6866006626. The cubic root of 649724123 is about 866.1165364882.

The spelling of 649724123 in words is "six hundred forty-nine million, seven hundred twenty-four thousand, one hundred twenty-three".