27728613421 has 4 divisors (see below), whose sum is σ = 28119157344. Its totient is φ = 27338069500.

The previous prime is 27728613397. The next prime is 27728613443. The reversal of 27728613421 is 12431682772.

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 27728613421 - 2⁵ = 27728613389 is a prime.

It is a super-2 number, since 2×27728613421² (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 (27728613461) 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, 195271855 + ... + 195271996.

It is an arithmetic number, because the mean of its divisors is an integer number (7029789336).

Almost surely, 2^27728613421 is an apocalyptic number.

It is an amenable number.

27728613421 is a deficient number, since it is larger than the sum of its proper divisors (390543923).

27728613421 is an equidigital number, since it uses as much as digits as its factorization.

27728613421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390543922.

The product of its digits is 225792, while the sum is 43.

The spelling of 27728613421 in words is "twenty-seven billion, seven hundred twenty-eight million, six hundred thirteen thousand, four hundred twenty-one".