661598928 has 100 divisors (see below), whose sum is σ = 2027565540. Its totient is φ = 207553536.

The previous prime is 661598923. The next prime is 661598929. The reversal of 661598928 is 829895166.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 602800704 + 58798224 = 24552^2 + 7668^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661598923) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7018 + ... + 37046.

Almost surely, 2^661598928 is an apocalyptic number.

661598928 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661598928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1013782770).

661598928 is an abundant number, since it is smaller than the sum of its proper divisors (1365966612).

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

661598928 is a wasteful number, since it uses less digits than its factorization.

661598928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30066 (or 30051 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 54.

The square root of 661598928 is about 25721.5654266998. The cubic root of 661598928 is about 871.3612933612.

The spelling of 661598928 in words is "six hundred sixty-one million, five hundred ninety-eight thousand, nine hundred twenty-eight".