21139248 has 80 divisors (see below), whose sum is σ = 61940480. Its totient is φ = 6158592.

The previous prime is 21139243. The next prime is 21139253. The reversal of 21139248 is 84293112.

It is an interprime number because it is at equal distance from previous prime (21139243) and next prime (21139253).

It is not an unprimeable number, because it can be changed into a prime (21139243) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10965 + ... + 12747.

It is an arithmetic number, because the mean of its divisors is an integer number (774256).

Almost surely, 2^21139248 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21139248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30970240).

21139248 is an abundant number, since it is smaller than the sum of its proper divisors (40801232).

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

21139248 is a wasteful number, since it uses less digits than its factorization.

21139248 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1826 (or 1820 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 21139248 is about 4597.7437945149. The cubic root of 21139248 is about 276.5008758162.

The spelling of 21139248 in words is "twenty-one million, one hundred thirty-nine thousand, two hundred forty-eight".