21005348 has 72 divisors (see below), whose sum is σ = 47714688. Its totient is φ = 7907328.

The previous prime is 21005339. The next prime is 21005363. The reversal of 21005348 is 84350012.

It is a super-2 number, since 2×21005348² = 882449289202208, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 108740 + ... + 108932.

It is an arithmetic number, because the mean of its divisors is an integer number (662704).

Almost surely, 2^21005348 is an apocalyptic number.

21005348 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21005348, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23857344).

21005348 is an abundant number, since it is smaller than the sum of its proper divisors (26709340).

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

21005348 is a wasteful number, since it uses less digits than its factorization.

21005348 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253 (or 238 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21005348 is about 4583.1591724486. The cubic root of 21005348 is about 275.9158358511.

21005348 divided by its sum of digits (23) gives a triangular number (913276 = T₁₃₅₁).

The spelling of 21005348 in words is "twenty-one million, five thousand, three hundred forty-eight".