2028399991 has 2 divisors, whose sum is σ = 2028399992. Its totient is φ = 2028399990.

The previous prime is 2028399949. The next prime is 2028400007. The reversal of 2028399991 is 1999938202.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2028399991 is a prime.

It is a super-2 number, since 2×2028399991² = 8228813046977600162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2028399691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1014199995 + 1014199996.

It is an arithmetic number, because the mean of its divisors is an integer number (1014199996).

Almost surely, 2^2028399991 is an apocalyptic number.

2028399991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2028399991 is an equidigital number, since it uses as much as digits as its factorization.

2028399991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 629856, while the sum is 52.

The square root of 2028399991 is about 45037.7618338212. The cubic root of 2028399991 is about 1265.8566670942.

The spelling of 2028399991 in words is "two billion, twenty-eight million, three hundred ninety-nine thousand, nine hundred ninety-one".