21928878 has 24 divisors (see below), whose sum is σ = 50308128. Its totient is φ = 6879552.

The previous prime is 21928877. The next prime is 21928883. The reversal of 21928878 is 87882912.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21928877) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35526 + ... + 36137.

It is an arithmetic number, because the mean of its divisors is an integer number (2096172).

Almost surely, 2^21928878 is an apocalyptic number.

21928878 is an abundant number, since it is smaller than the sum of its proper divisors (28379250).

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

21928878 is a wasteful number, since it uses less digits than its factorization.

21928878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71688 (or 71685 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 21928878 is about 4682.8279917161. The cubic root of 21928878 is about 279.9016576408.

The spelling of 21928878 in words is "twenty-one million, nine hundred twenty-eight thousand, eight hundred seventy-eight".