28219831 has 2 divisors, whose sum is σ = 28219832. Its totient is φ = 28219830.

The previous prime is 28219817. The next prime is 28219843. The reversal of 28219831 is 13891282.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28219831 is a prime.

It is a super-2 number, since 2×28219831² = 1592717723337122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28219861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14109915 + 14109916.

It is an arithmetic number, because the mean of its divisors is an integer number (14109916).

Almost surely, 2^28219831 is an apocalyptic number.

28219831 is a deficient number, since it is larger than the sum of its proper divisors (1).

28219831 is an equidigital number, since it uses as much as digits as its factorization.

28219831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 34.

The square root of 28219831 is about 5312.2340874626. The cubic root of 28219831 is about 304.4515126683.

The spelling of 28219831 in words is "twenty-eight million, two hundred nineteen thousand, eight hundred thirty-one".