1665677556 has 72 divisors (see below), whose sum is σ = 4329561600. Its totient is φ = 539683776.

The previous prime is 1665677551. The next prime is 1665677567. The reversal of 1665677556 is 6557765661.

1665677556 is a `hidden beast` number, since 1 + 6 + 6 + 567 + 75 + 5 + 6 = 666.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665677551) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 248805 + ... + 255411.

It is an arithmetic number, because the mean of its divisors is an integer number (60132800).

Almost surely, 2^1665677556 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 1665677556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2164780800).

1665677556 is an abundant number, since it is smaller than the sum of its proper divisors (2663884044).

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

1665677556 is a wasteful number, since it uses less digits than its factorization.

1665677556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6813 (or 6808 counting only the distinct ones).

The product of its digits is 7938000, while the sum is 54.

The square root of 1665677556 is about 40812.7131663652. The cubic root of 1665677556 is about 1185.3965110095.

The spelling of 1665677556 in words is "one billion, six hundred sixty-five million, six hundred seventy-seven thousand, five hundred fifty-six".