21158214 has 64 divisors (see below), whose sum is σ = 54093312. Its totient is φ = 5356800.

The previous prime is 21158201. The next prime is 21158231. The reversal of 21158214 is 41285112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18384 + ... + 19500.

It is an arithmetic number, because the mean of its divisors is an integer number (845208).

Almost surely, 2^21158214 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21158214, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27046656).

21158214 is an abundant number, since it is smaller than the sum of its proper divisors (32935098).

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

21158214 is a wasteful number, since it uses less digits than its factorization.

21158214 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1181.

The product of its digits is 640, while the sum is 24.

The square root of 21158214 is about 4599.8058654687. The cubic root of 21158214 is about 276.5835427125.

The spelling of 21158214 in words is "twenty-one million, one hundred fifty-eight thousand, two hundred fourteen".