21369761280 has 640 divisors, whose sum is σ = 89801395200. Its totient is φ = 4712988672.

The previous prime is 21369761261. The next prime is 21369761293. The reversal of 21369761280 is 8216796312.

21369761280 is a `hidden beast` number, since 2 + 1 + 369 + 7 + 6 + 1 + 280 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

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 63 ways as a sum of consecutive naturals, for example, 14030599 + ... + 14032121.

It is an arithmetic number, because the mean of its divisors is an integer number (140314680).

Almost surely, 2^21369761280 is an apocalyptic number.

21369761280 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 21369761280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44900697600).

21369761280 is an abundant number, since it is smaller than the sum of its proper divisors (68431633920).

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

21369761280 is a wasteful number, since it uses less digits than its factorization.

21369761280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1591 (or 1569 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The spelling of 21369761280 in words is "twenty-one billion, three hundred sixty-nine million, seven hundred sixty-one thousand, two hundred eighty".