28396431 has 36 divisors (see below), whose sum is σ = 50239800. Its totient is φ = 15367968.

The previous prime is 28396399. The next prime is 28396439. The reversal of 28396431 is 13469382.

28396431 is a `hidden beast` number, since 2 + 8 + 3 + 9 + 643 + 1 = 666.

It is not a de Polignac number, because 28396431 - 2⁵ = 28396399 is a prime.

It is a super-2 number, since 2×28396431² = 1612714587075522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28396439) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 6685 + ... + 10073.

It is an arithmetic number, because the mean of its divisors is an integer number (1395550).

Almost surely, 2^28396431 is an apocalyptic number.

28396431 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

28396431 is a deficient number, since it is larger than the sum of its proper divisors (21843369).

28396431 is a wasteful number, since it uses less digits than its factorization.

28396431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3428 (or 3418 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 28396431 is about 5328.8301718107. The cubic root of 28396431 is about 305.0852793872.

The spelling of 28396431 in words is "twenty-eight million, three hundred ninety-six thousand, four hundred thirty-one".