1661543356 has 12 divisors (see below), whose sum is σ = 3172037400. Its totient is φ = 755246960.

The previous prime is 1661543339. The next prime is 1661543419. The reversal of 1661543356 is 6533451661.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18881131 + ... + 18881218.

It is an arithmetic number, because the mean of its divisors is an integer number (264336450).

Almost surely, 2^1661543356 is an apocalyptic number.

It is an amenable number.

1661543356 is a deficient number, since it is larger than the sum of its proper divisors (1510494044).

1661543356 is a wasteful number, since it uses less digits than its factorization.

1661543356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37762364 (or 37762362 counting only the distinct ones).

The product of its digits is 194400, while the sum is 40.

The square root of 1661543356 is about 40762.0332662638. The cubic root of 1661543356 is about 1184.4149832400.

The spelling of 1661543356 in words is "one billion, six hundred sixty-one million, five hundred forty-three thousand, three hundred fifty-six".