649865823 has 4 divisors (see below), whose sum is σ = 866487768. Its totient is φ = 433243880.

The previous prime is 649865819. The next prime is 649865869. The reversal of 649865823 is 328568946.

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 649865823 - 2² = 649865819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649865123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108310968 + ... + 108310973.

It is an arithmetic number, because the mean of its divisors is an integer number (216621942).

Almost surely, 2^649865823 is an apocalyptic number.

649865823 is a deficient number, since it is larger than the sum of its proper divisors (216621945).

649865823 is a wasteful number, since it uses less digits than its factorization.

649865823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216621944.

The product of its digits is 2488320, while the sum is 51.

The square root of 649865823 is about 25492.4660046846. The cubic root of 649865823 is about 866.1794964368.

The spelling of 649865823 in words is "six hundred forty-nine million, eight hundred sixty-five thousand, eight hundred twenty-three".