28731919 has 2 divisors, whose sum is σ = 28731920. Its totient is φ = 28731918.

The previous prime is 28731917. The next prime is 28731931. The reversal of 28731919 is 91913782.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28731919 - 2¹ = 28731917 is a prime.

It is a super-2 number, since 2×28731919² = 1651046338845122, which contains 22 as substring.

Together with 28731917, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28731917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14365959 + 14365960.

It is an arithmetic number, because the mean of its divisors is an integer number (14365960).

Almost surely, 2^28731919 is an apocalyptic number.

28731919 is a deficient number, since it is larger than the sum of its proper divisors (1).

28731919 is an equidigital number, since it uses as much as digits as its factorization.

28731919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 40.

The square root of 28731919 is about 5360.2163202617. The cubic root of 28731919 is about 306.2820494572.

The spelling of 28731919 in words is "twenty-eight million, seven hundred thirty-one thousand, nine hundred nineteen".