1666986731 has 4 divisors (see below), whose sum is σ = 1765044792. Its totient is φ = 1568928672.

The previous prime is 1666986623. The next prime is 1666986743. The reversal of 1666986731 is 1376896661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666986731 is a prime.

It is a super-2 number, since 2×1666986731² = 5557689522660132722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666986131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49029005 + ... + 49029038.

It is an arithmetic number, because the mean of its divisors is an integer number (441261198).

Almost surely, 2^1666986731 is an apocalyptic number.

1666986731 is a deficient number, since it is larger than the sum of its proper divisors (98058061).

1666986731 is an equidigital number, since it uses as much as digits as its factorization.

1666986731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98058060.

The product of its digits is 1959552, while the sum is 53.

The square root of 1666986731 is about 40828.7488297156. The cubic root of 1666986731 is about 1185.7069922845.

The spelling of 1666986731 in words is "one billion, six hundred sixty-six million, nine hundred eighty-six thousand, seven hundred thirty-one".