28081802421 has 24 divisors (see below), whose sum is σ = 41856430304. Its totient is φ = 18128849760.

The previous prime is 28081802401. The next prime is 28081802429. The reversal of 28081802421 is 12420818082.

28081802421 is a `hidden beast` number, since 2 + 80 + 81 + 80 + 2 + 421 = 666.

It is not a de Polignac number, because 28081802421 - 2²³ = 28073413813 is a prime.

It is a super-2 number, since 2×28081802421² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28081802429) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 129571 + ... + 270096.

Almost surely, 2^28081802421 is an apocalyptic number.

It is an amenable number.

28081802421 is a deficient number, since it is larger than the sum of its proper divisors (13774627883).

28081802421 is a wasteful number, since it uses less digits than its factorization.

28081802421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399921 (or 399918 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 36.

The spelling of 28081802421 in words is "twenty-eight billion, eighty-one million, eight hundred two thousand, four hundred twenty-one".