28693421 has 4 divisors (see below), whose sum is σ = 28711644. Its totient is φ = 28675200.

The previous prime is 28693409. The next prime is 28693429. The reversal of 28693421 is 12439682.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3553225 + 25140196 = 1885^2 + 5014^2 .

It is a cyclic number.

It is not a de Polignac number, because 28693421 - 2¹⁴ = 28677037 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28693429) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6500 + ... + 9981.

It is an arithmetic number, because the mean of its divisors is an integer number (7177911).

Almost surely, 2^28693421 is an apocalyptic number.

It is an amenable number.

28693421 is a deficient number, since it is larger than the sum of its proper divisors (18223).

28693421 is a wasteful number, since it uses less digits than its factorization.

28693421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18222.

The product of its digits is 20736, while the sum is 35.

The square root of 28693421 is about 5356.6240301145. The cubic root of 28693421 is about 306.1451921796.

The spelling of 28693421 in words is "twenty-eight million, six hundred ninety-three thousand, four hundred twenty-one".