19928391 has 8 divisors (see below), whose sum is σ = 30367104. Its totient is φ = 11387640.

The previous prime is 19928353. The next prime is 19928401. The reversal of 19928391 is 19382991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 19928391 - 2⁹ = 19927879 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19920391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 474465 + ... + 474506.

It is an arithmetic number, because the mean of its divisors is an integer number (3795888).

Almost surely, 2^19928391 is an apocalyptic number.

19928391 is a deficient number, since it is larger than the sum of its proper divisors (10438713).

19928391 is an equidigital number, since it uses as much as digits as its factorization.

19928391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 948981.

The product of its digits is 34992, while the sum is 42.

The square root of 19928391 is about 4464.1226461646. The cubic root of 19928391 is about 271.1174130277.

The spelling of 19928391 in words is "nineteen million, nine hundred twenty-eight thousand, three hundred ninety-one".