28278352421 has 4 divisors (see below), whose sum is σ = 30849111744. Its totient is φ = 25707593100.

The previous prime is 28278352397. The next prime is 28278352423. The reversal of 28278352421 is 12425387282.

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 28278352421 - 2⁶ = 28278352357 is a prime.

It is a super-2 number, since 2×28278352421² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28278352423) 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, 1285379645 + ... + 1285379666.

It is an arithmetic number, because the mean of its divisors is an integer number (7712277936).

Almost surely, 2^28278352421 is an apocalyptic number.

It is an amenable number.

28278352421 is a deficient number, since it is larger than the sum of its proper divisors (2570759323).

28278352421 is a wasteful number, since it uses less digits than its factorization.

28278352421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2570759322.

The product of its digits is 430080, while the sum is 44.

The spelling of 28278352421 in words is "twenty-eight billion, two hundred seventy-eight million, three hundred fifty-two thousand, four hundred twenty-one".