1661344564 has 12 divisors (see below), whose sum is σ = 3171657888. Its totient is φ = 755156600.

The previous prime is 1661344543. The next prime is 1661344589. The reversal of 1661344564 is 4654431661.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18878872 + ... + 18878959.

It is an arithmetic number, because the mean of its divisors is an integer number (264304824).

Almost surely, 2^1661344564 is an apocalyptic number.

It is an amenable number.

1661344564 is a deficient number, since it is larger than the sum of its proper divisors (1510313324).

1661344564 is a wasteful number, since it uses less digits than its factorization.

1661344564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37757846 (or 37757844 counting only the distinct ones).

The product of its digits is 207360, while the sum is 40.

The square root of 1661344564 is about 40759.5947477401. The cubic root of 1661344564 is about 1184.3677457097.

The spelling of 1661344564 in words is "one billion, six hundred sixty-one million, three hundred forty-four thousand, five hundred sixty-four".