21206014380 has 384 divisors, whose sum is σ = 72928665600. Its totient is φ = 5094835200.

The previous prime is 21206014343. The next prime is 21206014381. The reversal of 21206014380 is 8341060212.

21206014380 is a `hidden beast` number, since 2 + 1 + 20 + 601 + 4 + 38 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21206014381) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 19401114 + ... + 19402206.

It is an arithmetic number, because the mean of its divisors is an integer number (189918400).

Almost surely, 2^21206014380 is an apocalyptic number.

21206014380 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 21206014380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36464332800).

21206014380 is an abundant number, since it is smaller than the sum of its proper divisors (51722651220).

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

21206014380 is a wasteful number, since it uses less digits than its factorization.

21206014380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222 (or 1214 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

Adding to 21206014380 its reverse (8341060212), we get a palindrome (29547074592).

The spelling of 21206014380 in words is "twenty-one billion, two hundred six million, fourteen thousand, three hundred eighty".