661571652 has 96 divisors (see below), whose sum is σ = 1809609984. Its totient is φ = 184204800.

The previous prime is 661571629. The next prime is 661571663. The reversal of 661571652 is 256175166.

It is a self number, because there is not a number n which added to its sum of digits gives 661571652.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 805402 + ... + 806222.

It is an arithmetic number, because the mean of its divisors is an integer number (18850104).

Almost surely, 2^661571652 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 661571652, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (904804992).

661571652 is an abundant number, since it is smaller than the sum of its proper divisors (1148038332).

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

661571652 is a wasteful number, since it uses less digits than its factorization.

661571652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1069 (or 1067 counting only the distinct ones).

The product of its digits is 75600, while the sum is 39.

The square root of 661571652 is about 25721.0352046725. The cubic root of 661571652 is about 871.3493185447.

The spelling of 661571652 in words is "six hundred sixty-one million, five hundred seventy-one thousand, six hundred fifty-two".