649875691 has 4 divisors (see below), whose sum is σ = 650366752. Its totient is φ = 649384632.

The previous prime is 649875683. The next prime is 649875731. The reversal of 649875691 is 196578946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 196578946 = 2 ⋅98289473.

It is a cyclic number.

It is not a de Polignac number, because 649875691 - 2³ = 649875683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649875631) 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, 243540 + ... + 246193.

It is an arithmetic number, because the mean of its divisors is an integer number (162591688).

Almost surely, 2^649875691 is an apocalyptic number.

649875691 is a deficient number, since it is larger than the sum of its proper divisors (491061).

649875691 is a wasteful number, since it uses less digits than its factorization.

649875691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491060.

The product of its digits is 3265920, while the sum is 55.

The square root of 649875691 is about 25492.6595513297. The cubic root of 649875691 is about 866.1838806321.

The spelling of 649875691 in words is "six hundred forty-nine million, eight hundred seventy-five thousand, six hundred ninety-one".