28966421 has 4 divisors (see below), whose sum is σ = 31599744. Its totient is φ = 26333100.

The previous prime is 28966417. The next prime is 28966471. The reversal of 28966421 is 12466982.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28966421 - 2² = 28966417 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28966411) 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, 1316645 + ... + 1316666.

It is an arithmetic number, because the mean of its divisors is an integer number (7899936).

Almost surely, 2^28966421 is an apocalyptic number.

It is an amenable number.

28966421 is a deficient number, since it is larger than the sum of its proper divisors (2633323).

28966421 is a wasteful number, since it uses less digits than its factorization.

28966421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2633322.

The product of its digits is 41472, while the sum is 38.

The square root of 28966421 is about 5382.0461722286. The cubic root of 28966421 is about 307.1130559357.

The spelling of 28966421 in words is "twenty-eight million, nine hundred sixty-six thousand, four hundred twenty-one".