661419648 has 256 divisors, whose sum is σ = 2088633600. Its totient is φ = 205590528.

The previous prime is 661419643. The next prime is 661419691. The reversal of 661419648 is 846914166.

It is a nude number because it is divisible by every one of its digits.

Its product of digits (248832) is a multiple of the sum of its prime factors (256).

It is not an unprimeable number, because it can be changed into a prime (661419641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4212786 + ... + 4212942.

It is an arithmetic number, because the mean of its divisors is an integer number (8158725).

Almost surely, 2^661419648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661419648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1044316800).

661419648 is an abundant number, since it is smaller than the sum of its proper divisors (1427213952).

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

661419648 is a wasteful number, since it uses less digits than its factorization.

661419648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256 (or 238 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 661419648 is about 25718.0801771827. The cubic root of 661419648 is about 871.2825791237.

It can be divided in two parts, 6614 and 19648, that added together give a palindrome (26262).

The spelling of 661419648 in words is "six hundred sixty-one million, four hundred nineteen thousand, six hundred forty-eight".