1621664665180 has 48 divisors (see below), whose sum is σ = 3892080890880. Its totient is φ = 555987071808.

The previous prime is 1621664665171. The next prime is 1621664665217. The reversal of 1621664665180 is 815664661261.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8179261 + ... + 8375179.

It is an arithmetic number, because the mean of its divisors is an integer number (81085018560).

Almost surely, 2^{1621664665180} is an apocalyptic number.

1621664665180 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1621664665180 is an abundant number, since it is smaller than the sum of its proper divisors (2270416225700).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1621664665180 is a wasteful number, since it uses less digits than its factorization.

1621664665180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255058 (or 255056 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 52.

The spelling of 1621664665180 in words is "one trillion, six hundred twenty-one billion, six hundred sixty-four million, six hundred sixty-five thousand, one hundred eighty".