21878148 has 12 divisors (see below), whose sum is σ = 51049040. Its totient is φ = 7292712.

The previous prime is 21878123. The next prime is 21878149. The reversal of 21878148 is 84187812.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-3 number, since 3×21878148³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21878149) 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, 911578 + ... + 911601.

Almost surely, 2^21878148 is an apocalyptic number.

It is an amenable number.

21878148 is an abundant number, since it is smaller than the sum of its proper divisors (29170892).

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

21878148 is a wasteful number, since it uses less digits than its factorization.

21878148 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1823186 (or 1823184 counting only the distinct ones).

The product of its digits is 28672, while the sum is 39.

The square root of 21878148 is about 4677.4082567165. The cubic root of 21878148 is about 279.6856506208.

The spelling of 21878148 in words is "twenty-one million, eight hundred seventy-eight thousand, one hundred forty-eight".