28511421 has 16 divisors (see below), whose sum is σ = 39813120. Its totient is φ = 18114800.

The previous prime is 28511411. The next prime is 28511443. The reversal of 28511421 is 12411582.

It is not a de Polignac number, because 28511421 - 2⁵ = 28511389 is a prime.

It is a super-2 number, since 2×28511421² = 1625802254878482, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28511391 and 28511400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28511411) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24196 + ... + 25346.

It is an arithmetic number, because the mean of its divisors is an integer number (2488320).

Almost surely, 2^28511421 is an apocalyptic number.

It is an amenable number.

28511421 is a deficient number, since it is larger than the sum of its proper divisors (11301699).

28511421 is a wasteful number, since it uses less digits than its factorization.

28511421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1536.

The product of its digits is 640, while the sum is 24.

The square root of 28511421 is about 5339.6086935280. The cubic root of 28511421 is about 305.4965342212.

The spelling of 28511421 in words is "twenty-eight million, five hundred eleven thousand, four hundred twenty-one".