21461993280 has 896 divisors, whose sum is σ = 94615772160. Its totient is φ = 4514807808.

The previous prime is 21461993263. The next prime is 21461993297. The reversal of 21461993280 is 8239916412.

21461993280 is a `hidden beast` number, since 2 + 1 + 4 + 619 + 9 + 3 + 28 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21461993263) and next prime (21461993297).

It is a Harshad number since it is a multiple of its sum of digits (45).

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 127 ways as a sum of consecutive naturals, for example, 63685272 + ... + 63685608.

It is an arithmetic number, because the mean of its divisors is an integer number (105597960).

Almost surely, 2^21461993280 is an apocalyptic number.

21461993280 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 21461993280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47307886080).

21461993280 is an abundant number, since it is smaller than the sum of its proper divisors (73153778880).

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

21461993280 is an equidigital number, since it uses as much as digits as its factorization.

21461993280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395 (or 367 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The spelling of 21461993280 in words is "twenty-one billion, four hundred sixty-one million, nine hundred ninety-three thousand, two hundred eighty".