21939197280 has 864 divisors, whose sum is σ = 95321917152. Its totient is φ = 4201021440.

The previous prime is 21939197279. The next prime is 21939197299. The reversal of 21939197280 is 8279193912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 36996664 + ... + 36997256.

It is an arithmetic number, because the mean of its divisors is an integer number (110326293).

Almost surely, 2^21939197280 is an apocalyptic number.

21939197280 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 21939197280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47660958576).

21939197280 is an abundant number, since it is smaller than the sum of its proper divisors (73382719872).

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

21939197280 is a wasteful number, since it uses less digits than its factorization.

21939197280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660 (or 634 counting only the distinct ones).

The product of its (nonzero) digits is 489888, while the sum is 51.

The spelling of 21939197280 in words is "twenty-one billion, nine hundred thirty-nine million, one hundred ninety-seven thousand, two hundred eighty".