1665216554 has 4 divisors (see below), whose sum is σ = 2497824834. Its totient is φ = 832608276.

The previous prime is 1665216551. The next prime is 1665216559. The reversal of 1665216554 is 4556125661.

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

It can be written as a sum of positive squares in only one way, i.e., 1658688529 + 6528025 = 40727^2 + 2555^2 .

It is not an unprimeable number, because it can be changed into a prime (1665216551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 416304137 + ... + 416304140.

Almost surely, 2^1665216554 is an apocalyptic number.

1665216554 is a deficient number, since it is larger than the sum of its proper divisors (832608280).

1665216554 is an equidigital number, since it uses as much as digits as its factorization.

1665216554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 832608279.

The product of its digits is 216000, while the sum is 41.

The square root of 1665216554 is about 40807.0650010510. The cubic root of 1665216554 is about 1185.2871419857.

The spelling of 1665216554 in words is "one billion, six hundred sixty-five million, two hundred sixteen thousand, five hundred fifty-four".