649156891 has 4 divisors (see below), whose sum is σ = 650897632. Its totient is φ = 647416152.

The previous prime is 649156829. The next prime is 649156919. The reversal of 649156891 is 198651946.

649156891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198651946 = 2 ⋅99325973.

It is a cyclic number.

It is not a de Polignac number, because 649156891 - 2²³ = 640768283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649156801) 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, 869811 + ... + 870556.

It is an arithmetic number, because the mean of its divisors is an integer number (162724408).

Almost surely, 2^649156891 is an apocalyptic number.

649156891 is a deficient number, since it is larger than the sum of its proper divisors (1740741).

649156891 is a wasteful number, since it uses less digits than its factorization.

649156891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1740740.

The product of its digits is 466560, while the sum is 49.

The square root of 649156891 is about 25478.5574748650. The cubic root of 649156891 is about 865.8644130417.

The spelling of 649156891 in words is "six hundred forty-nine million, one hundred fifty-six thousand, eight hundred ninety-one".