661005072 has 240 divisors, whose sum is σ = 2311324288. Its totient is φ = 171694080.

The previous prime is 661005071. The next prime is 661005083. The reversal of 661005072 is 270500166.

It is not an unprimeable number, because it can be changed into a prime (661005071) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 956247 + ... + 956937.

Almost surely, 2^661005072 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 661005072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1155662144).

661005072 is an abundant number, since it is smaller than the sum of its proper divisors (1650319216).

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

661005072 is a wasteful number, since it uses less digits than its factorization.

661005072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798 (or 789 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 661005072 is about 25710.0189031436. The cubic root of 661005072 is about 871.1005019089.

The spelling of 661005072 in words is "six hundred sixty-one million, five thousand, seventy-two".