649840881 has 8 divisors (see below), whose sum is σ = 869539104. Its totient is φ = 431684960.

The previous prime is 649840859. The next prime is 649840889. The reversal of 649840881 is 188048946.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 649840881 - 2⁹ = 649840369 is a prime.

It is a super-2 number, since 2×649840881² = 844586341237712322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 649840881.

It is not an unprimeable number, because it can be changed into a prime (649840889) 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 7 ways as a sum of consecutive naturals, for example, 384591 + ... + 386276.

It is an arithmetic number, because the mean of its divisors is an integer number (108692388).

Almost surely, 2^649840881 is an apocalyptic number.

It is an amenable number.

649840881 is a deficient number, since it is larger than the sum of its proper divisors (219698223).

649840881 is a wasteful number, since it uses less digits than its factorization.

649840881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 771151.

The product of its (nonzero) digits is 442368, while the sum is 48.

The square root of 649840881 is about 25491.9767966315. The cubic root of 649840881 is about 866.1684149055.

The spelling of 649840881 in words is "six hundred forty-nine million, eight hundred forty thousand, eight hundred eighty-one".