21392220 has 48 divisors (see below), whose sum is σ = 60923520. Its totient is φ = 5606976.

The previous prime is 21392213. The next prime is 21392221. The reversal of 21392220 is 2229312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21392221) 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, 519 + ... + 6561.

It is an arithmetic number, because the mean of its divisors is an integer number (1269240).

Almost surely, 2^21392220 is an apocalyptic number.

21392220 is a gapful number since it is divisible by the number (20) 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 21392220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30461760).

21392220 is an abundant number, since it is smaller than the sum of its proper divisors (39531300).

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

21392220 is a wasteful number, since it uses less digits than its factorization.

21392220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6114 (or 6112 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 21392220 is about 4625.1724292182. The cubic root of 21392220 is about 277.5994611411.

It can be divided in two parts, 21392 and 220, that added together give a palindrome (21612).

The spelling of 21392220 in words is "twenty-one million, three hundred ninety-two thousand, two hundred twenty".