21929238 has 32 divisors (see below), whose sum is σ = 49564800. Its totient is φ = 7184808.

The previous prime is 21929233. The next prime is 21929263. The reversal of 21929238 is 83292912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21929231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 256 + ... + 6627.

It is an arithmetic number, because the mean of its divisors is an integer number (1548900).

Almost surely, 2^21929238 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21929238, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24782400).

21929238 is an abundant number, since it is smaller than the sum of its proper divisors (27635562).

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

21929238 is a wasteful number, since it uses less digits than its factorization.

21929238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6953 (or 6947 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 21929238 is about 4682.8664298696. The cubic root of 21929238 is about 279.9031893204.

The spelling of 21929238 in words is "twenty-one million, nine hundred twenty-nine thousand, two hundred thirty-eight".