1028047781 has 4 divisors (see below), whose sum is σ = 1028865600. Its totient is φ = 1027229964.

The previous prime is 1028047771. The next prime is 1028047789. The reversal of 1028047781 is 1877408201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1877408201 = 181 ⋅10372421.

It is a cyclic number.

It is not a de Polignac number, because 1028047781 - 2¹⁰ = 1028046757 is a prime.

It is a super-2 number, since 2×1028047781² = 2113764480038047922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1028047789) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 407021 + ... + 409538.

It is an arithmetic number, because the mean of its divisors is an integer number (257216400).

Almost surely, 2^1028047781 is an apocalyptic number.

It is an amenable number.

1028047781 is a deficient number, since it is larger than the sum of its proper divisors (817819).

1028047781 is an equidigital number, since it uses as much as digits as its factorization.

1028047781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 817818.

The product of its (nonzero) digits is 25088, while the sum is 38.

The square root of 1028047781 is about 32063.1841993274. The cubic root of 1028047781 is about 1009.2631887203.

The spelling of 1028047781 in words is "one billion, twenty-eight million, forty-seven thousand, seven hundred eighty-one".