661021552 has 40 divisors (see below), whose sum is σ = 1353663360. Its totient is φ = 311832000.

The previous prime is 661021547. The next prime is 661021607. The reversal of 661021552 is 255120166.

661021552 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 661021552.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71973 + ... + 80635.

It is an arithmetic number, because the mean of its divisors is an integer number (33841584).

Almost surely, 2^661021552 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 661021552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (676831680).

661021552 is an abundant number, since it is smaller than the sum of its proper divisors (692641808).

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

661021552 is a wasteful number, since it uses less digits than its factorization.

661021552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8941 (or 8935 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 661021552 is about 25710.3393987711. The cubic root of 661021552 is about 871.1077411963.

The spelling of 661021552 in words is "six hundred sixty-one million, twenty-one thousand, five hundred fifty-two".