1665211216 has 20 divisors (see below), whose sum is σ = 3250979424. Its totient is φ = 826248800.

The previous prime is 1665211211. The next prime is 1665211241. The reversal of 1665211216 is 6121125661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665211211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 395140 + ... + 399331.

Almost surely, 2^1665211216 is an apocalyptic number.

1665211216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1665211216 is a deficient number, since it is larger than the sum of its proper divisors (1585768208).

1665211216 is a wasteful number, since it uses less digits than its factorization.

1665211216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 794610 (or 794604 counting only the distinct ones).

The product of its digits is 4320, while the sum is 31.

The square root of 1665211216 is about 40806.9995956576. Note that the first 3 decimals coincide. The cubic root of 1665211216 is about 1185.2858754699.

Adding to 1665211216 its reverse (6121125661), we get a palindrome (7786336877).

The spelling of 1665211216 in words is "one billion, six hundred sixty-five million, two hundred eleven thousand, two hundred sixteen".