1028820389 has 2 divisors, whose sum is σ = 1028820390. Its totient is φ = 1028820388.

The previous prime is 1028820361. The next prime is 1028820391. The reversal of 1028820389 is 9830288201.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 569061025 + 459759364 = 23855^2 + 21442^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1028820389 is a prime.

It is a super-2 number, since 2×1028820389² = 2116942785644222642, which contains 22 as substring.

Together with 1028820391, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1028820319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 514410194 + 514410195.

It is an arithmetic number, because the mean of its divisors is an integer number (514410195).

Almost surely, 2^1028820389 is an apocalyptic number.

It is an amenable number.

1028820389 is a deficient number, since it is larger than the sum of its proper divisors (1).

1028820389 is an equidigital number, since it uses as much as digits as its factorization.

1028820389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 41.

The square root of 1028820389 is about 32075.2301472647. The cubic root of 1028820389 is about 1009.5159556866.

The spelling of 1028820389 in words is "one billion, twenty-eight million, eight hundred twenty thousand, three hundred eighty-nine".