28202391 has 24 divisors (see below), whose sum is σ = 48605040. Its totient is φ = 16114896.

The previous prime is 28202389. The next prime is 28202401. The reversal of 28202391 is 19320282.

It is a happy number.

It is not a de Polignac number, because 28202391 - 2¹ = 28202389 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28202351) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9336 + ... + 11981.

It is an arithmetic number, because the mean of its divisors is an integer number (2025210).

Almost surely, 2^28202391 is an apocalyptic number.

28202391 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

28202391 is a deficient number, since it is larger than the sum of its proper divisors (20402649).

28202391 is a wasteful number, since it uses less digits than its factorization.

28202391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21340 (or 21327 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 28202391 is about 5310.5923398431. The cubic root of 28202391 is about 304.3887822129.

The spelling of 28202391 in words is "twenty-eight million, two hundred two thousand, three hundred ninety-one".