1661533600 has 36 divisors (see below), whose sum is σ = 4056220854. Its totient is φ = 664613120.

The previous prime is 1661533561. The next prime is 1661533649. The reversal of 1661533600 is 63351661.

It can be written as a sum of positive squares in 3 ways, for example, as 1427932944 + 233600656 = 37788^2 + 15284^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1037659 + ... + 1039258.

Almost surely, 2^1661533600 is an apocalyptic number.

1661533600 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1661533600 is an abundant number, since it is smaller than the sum of its proper divisors (2394687254).

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

1661533600 is a wasteful number, since it uses less digits than its factorization.

1661533600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2076937 (or 2076924 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 31.

The square root of 1661533600 is about 40761.9135959047. The cubic root of 1661533600 is about 1184.4126650790.

The spelling of 1661533600 in words is "one billion, six hundred sixty-one million, five hundred thirty-three thousand, six hundred".