1641988818 has 18 divisors (see below), whose sum is σ = 3558014967. Its totient is φ = 547272300.

The previous prime is 1641988801. The next prime is 1641988819. The reversal of 1641988818 is 8188891461.

It is a happy number.

1641988818 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 820994409 + 820994409 = 28653^2 + 28653^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=28653.

It is a super-2 number, since 2×1641988818² = 5392254556874074248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1641988819) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 167143 + ... + 176693.

Almost surely, 2^1641988818 is an apocalyptic number.

1641988818 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1641988818 is an abundant number, since it is smaller than the sum of its proper divisors (1916026149).

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

1641988818 is an frugal number, since it uses more digits than its factorization.

1641988818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19110 (or 9556 counting only the distinct ones).

The product of its digits is 884736, while the sum is 54.

The square root of 1641988818 is about 40521.4612026763. The cubic root of 1641988818 is about 1179.7502147720.

The spelling of 1641988818 in words is "one billion, six hundred forty-one million, nine hundred eighty-eight thousand, eight hundred eighteen".