1661210216 has 32 divisors (see below), whose sum is σ = 3316464000. Its totient is φ = 777367296.

The previous prime is 1661210191. The next prime is 1661210227. The reversal of 1661210216 is 6120121661.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 9776 + ... + 58463.

It is an arithmetic number, because the mean of its divisors is an integer number (103639500).

Almost surely, 2^1661210216 is an apocalyptic number.

It is an amenable number.

1661210216 is a deficient number, since it is larger than the sum of its proper divisors (1655253784).

1661210216 is a wasteful number, since it uses less digits than its factorization.

1661210216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68441 (or 68437 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 1661210216 is about 40757.9466607434. The cubic root of 1661210216 is about 1184.3358194152.

Adding to 1661210216 its reverse (6120121661), we get a palindrome (7781331877).

The spelling of 1661210216 in words is "one billion, six hundred sixty-one million, two hundred ten thousand, two hundred sixteen".