28190421 has 12 divisors (see below), whose sum is σ = 46536672. Its totient is φ = 16108776.

The previous prime is 28190419. The next prime is 28190423. The reversal of 28190421 is 12409182.

It is an interprime number because it is at equal distance from previous prime (28190419) and next prime (28190423).

It is not a de Polignac number, because 28190421 - 2¹ = 28190419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28190423) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 223671 + ... + 223796.

It is an arithmetic number, because the mean of its divisors is an integer number (3878056).

Almost surely, 2^28190421 is an apocalyptic number.

28190421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28190421 is a deficient number, since it is larger than the sum of its proper divisors (18346251).

28190421 is a wasteful number, since it uses less digits than its factorization.

28190421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447480 (or 447477 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 28190421 is about 5309.4652273087. The cubic root of 28190421 is about 304.3457119957.

The spelling of 28190421 in words is "twenty-eight million, one hundred ninety thousand, four hundred twenty-one".