1661356143 has 16 divisors (see below), whose sum is σ = 2590809600. Its totient is φ = 1049277240.

The previous prime is 1661356139. The next prime is 1661356189. The reversal of 1661356143 is 3416531661.

1661356143 is a `hidden beast` number, since 1 + 6 + 6 + 1 + 35 + 614 + 3 = 666.

It is not a de Polignac number, because 1661356143 - 2² = 1661356139 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 1661356098 and 1661356107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661356133) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1618743 + ... + 1619768.

It is an arithmetic number, because the mean of its divisors is an integer number (161925600).

Almost surely, 2^1661356143 is an apocalyptic number.

1661356143 is a deficient number, since it is larger than the sum of its proper divisors (929453457).

1661356143 is a wasteful number, since it uses less digits than its factorization.

1661356143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3238539 (or 3238533 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 1661356143 is about 40759.7367876683. The cubic root of 1661356143 is about 1184.3704972485.

The spelling of 1661356143 in words is "one billion, six hundred sixty-one million, three hundred fifty-six thousand, one hundred forty-three".