1665686474 has 4 divisors (see below), whose sum is σ = 2498529714. Its totient is φ = 832843236.

The previous prime is 1665686431. The next prime is 1665686497. The reversal of 1665686474 is 4746865661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 4746865661 = 73 ⋅65025557.

It can be written as a sum of positive squares in only one way, i.e., 1074856225 + 590830249 = 32785^2 + 24307^2 .

It is a super-2 number, since 2×1665686474² = 5549022859333105352, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 416421617 + ... + 416421620.

Almost surely, 2^1665686474 is an apocalyptic number.

1665686474 is a deficient number, since it is larger than the sum of its proper divisors (832843240).

1665686474 is an equidigital number, since it uses as much as digits as its factorization.

1665686474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 832843239.

The product of its digits is 5806080, while the sum is 53.

The square root of 1665686474 is about 40812.8224213910. The cubic root of 1665686474 is about 1185.3986265345.

The spelling of 1665686474 in words is "one billion, six hundred sixty-five million, six hundred eighty-six thousand, four hundred seventy-four".