649400989 has 4 divisors (see below), whose sum is σ = 670349440. Its totient is φ = 628452540.

The previous prime is 649400959. The next prime is 649400993. The reversal of 649400989 is 989004946.

649400989 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 a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 989004946 = 2 ⋅494502473.

It is a cyclic number.

It is not a de Polignac number, because 649400989 - 2¹³ = 649392797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649400909) 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, 10474179 + ... + 10474240.

It is an arithmetic number, because the mean of its divisors is an integer number (167587360).

Almost surely, 2^649400989 is an apocalyptic number.

It is an amenable number.

649400989 is a deficient number, since it is larger than the sum of its proper divisors (20948451).

649400989 is a wasteful number, since it uses less digits than its factorization.

649400989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20948450.

The product of its (nonzero) digits is 559872, while the sum is 49.

The square root of 649400989 is about 25483.3472879840. The cubic root of 649400989 is about 865.9729277877.

The spelling of 649400989 in words is "six hundred forty-nine million, four hundred thousand, nine hundred eighty-nine".