649112781 has 16 divisors (see below), whose sum is σ = 875941056. Its totient is φ = 427545216.

The previous prime is 649112747. The next prime is 649112791. The reversal of 649112781 is 187211946.

649112781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-649112781 is a prime.

It is a super-2 number, since 2×649112781² = 842694804915107922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649112701) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 80761 + ... + 88433.

It is an arithmetic number, because the mean of its divisors is an integer number (54746316).

Almost surely, 2^649112781 is an apocalyptic number.

It is an amenable number.

649112781 is a deficient number, since it is larger than the sum of its proper divisors (226828275).

649112781 is a wasteful number, since it uses less digits than its factorization.

649112781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8012.

The product of its digits is 24192, while the sum is 39.

The square root of 649112781 is about 25477.6918303052. The cubic root of 649112781 is about 865.8448008622.

The spelling of 649112781 in words is "six hundred forty-nine million, one hundred twelve thousand, seven hundred eighty-one".