1028181821 has 8 divisors (see below), whose sum is σ = 1048599000. Its totient is φ = 1007802432.

The previous prime is 1028181793. The next prime is 1028181871. The reversal of 1028181821 is 1281818201.

It can be written as a sum of positive squares in 4 ways, for example, as 298425625 + 729756196 = 17275^2 + 27014^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1028181821 - 2¹⁸ = 1027919677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1028181871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49055 + ... + 66803.

It is an arithmetic number, because the mean of its divisors is an integer number (131074875).

Almost surely, 2^1028181821 is an apocalyptic number.

It is an amenable number.

1028181821 is a deficient number, since it is larger than the sum of its proper divisors (20417179).

1028181821 is a wasteful number, since it uses less digits than its factorization.

1028181821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18895.

The product of its (nonzero) digits is 2048, while the sum is 32.

The square root of 1028181821 is about 32065.2743789914. The cubic root of 1028181821 is about 1009.3070504166.

The spelling of 1028181821 in words is "one billion, twenty-eight million, one hundred eighty-one thousand, eight hundred twenty-one".