28494921 has 72 divisors (see below), whose sum is σ = 50736384. Its totient is φ = 14152320.

The previous prime is 28494913. The next prime is 28494923. The reversal of 28494921 is 12949482.

It is not a de Polignac number, because 28494921 - 2³ = 28494913 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 28494921.

It is not an unprimeable number, because it can be changed into a prime (28494923) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 770115 + ... + 770151.

It is an arithmetic number, because the mean of its divisors is an integer number (704672).

Almost surely, 2^28494921 is an apocalyptic number.

28494921 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28494921 is a deficient number, since it is larger than the sum of its proper divisors (22241463).

28494921 is a wasteful number, since it uses less digits than its factorization.

28494921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111 (or 91 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 28494921 is about 5338.0634128867. The cubic root of 28494921 is about 305.4375909939.

The spelling of 28494921 in words is "twenty-eight million, four hundred ninety-four thousand, nine hundred twenty-one".