28720332919 has 4 divisors (see below), whose sum is σ = 28864656400. Its totient is φ = 28576009440.

The previous prime is 28720332889. The next prime is 28720332941. The reversal of 28720332919 is 91923302782.

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 28720332919 - 2¹³ = 28720324727 is a prime.

It is a super-2 number, since 2×28720332919² (a number of 22 digits) 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 (28720332419) 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, 72161442 + ... + 72161839.

It is an arithmetic number, because the mean of its divisors is an integer number (7216164100).

Almost surely, 2^28720332919 is an apocalyptic number.

28720332919 is a deficient number, since it is larger than the sum of its proper divisors (144323481).

28720332919 is a wasteful number, since it uses less digits than its factorization.

28720332919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144323480.

The product of its (nonzero) digits is 326592, while the sum is 46.

The spelling of 28720332919 in words is "twenty-eight billion, seven hundred twenty million, three hundred thirty-two thousand, nine hundred nineteen".