102028391 has 4 divisors (see below), whose sum is σ = 106464432. Its totient is φ = 97592352.

The previous prime is 102028387. The next prime is 102028393. The reversal of 102028391 is 193820201.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 102028391 - 2² = 102028387 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 102028391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102028393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2217986 + ... + 2218031.

It is an arithmetic number, because the mean of its divisors is an integer number (26616108).

Almost surely, 2^102028391 is an apocalyptic number.

102028391 is a deficient number, since it is larger than the sum of its proper divisors (4436041).

102028391 is an equidigital number, since it uses as much as digits as its factorization.

102028391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4436040.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 102028391 is about 10100.9104045131. The cubic root of 102028391 is about 467.2762191686.

Adding to 102028391 its reverse (193820201), we get a palindrome (295848592).

The spelling of 102028391 in words is "one hundred two million, twenty-eight thousand, three hundred ninety-one".