648778986 has 48 divisors (see below), whose sum is σ = 1491721920. Its totient is φ = 203343360.

The previous prime is 648778967. The next prime is 648778987. The reversal of 648778986 is 689877846.

648778986 is a `hidden beast` number, since 6 + 487 + 78 + 9 + 86 = 666.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (648778987) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11146 + ... + 37706.

It is an arithmetic number, because the mean of its divisors is an integer number (31077540).

Almost surely, 2^648778986 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 648778986, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (745860960).

648778986 is an abundant number, since it is smaller than the sum of its proper divisors (842942934).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

648778986 is a wasteful number, since it uses less digits than its factorization.

648778986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26651 (or 26648 counting only the distinct ones).

The product of its digits is 32514048, while the sum is 63.

The square root of 648778986 is about 25471.1402571616. The cubic root of 648778986 is about 865.6963601864.

The spelling of 648778986 in words is "six hundred forty-eight million, seven hundred seventy-eight thousand, nine hundred eighty-six".