1928112721 has 4 divisors (see below), whose sum is σ = 1938207744. Its totient is φ = 1918017700.

The previous prime is 1928112629. The next prime is 1928112727. The reversal of 1928112721 is 1272118291.

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.

It is a cyclic number.

It is not a de Polignac number, because 1928112721 - 2²¹ = 1926015569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1928112727) 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, 5047225 + ... + 5047606.

It is an arithmetic number, because the mean of its divisors is an integer number (484551936).

Almost surely, 2^1928112721 is an apocalyptic number.

It is an amenable number.

1928112721 is a deficient number, since it is larger than the sum of its proper divisors (10095023).

1928112721 is a wasteful number, since it uses less digits than its factorization.

1928112721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10095022.

The product of its digits is 4032, while the sum is 34.

The square root of 1928112721 is about 43910.2803566545. The cubic root of 1928112721 is about 1244.6411057799.

The spelling of 1928112721 in words is "one billion, nine hundred twenty-eight million, one hundred twelve thousand, seven hundred twenty-one".