21427878144 has 36 divisors (see below), whose sum is σ = 57029406896. Its totient is φ = 7142625792.

The previous prime is 21427878139. The next prime is 21427878209. The reversal of 21427878144 is 44187872412.

It is a super-2 number, since 2×21427878144² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a junction number, because it is equal to n+sod(n) for n = 21427878093 and 21427878102.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13949674 + ... + 13951209.

Almost surely, 2^21427878144 is an apocalyptic number.

21427878144 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21427878144 is an abundant number, since it is smaller than the sum of its proper divisors (35601528752).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21427878144 is an equidigital number, since it uses as much as digits as its factorization.

21427878144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27900902 (or 27900888 counting only the distinct ones).

The product of its digits is 802816, while the sum is 48.

The spelling of 21427878144 in words is "twenty-one billion, four hundred twenty-seven million, eight hundred seventy-eight thousand, one hundred forty-four".