21279959280 has 160 divisors (see below), whose sum is σ = 73346644800. Its totient is φ = 5670862848.

The previous prime is 21279959263. The next prime is 21279959297. The reversal of 21279959280 is 8295997212.

21279959280 is a `hidden beast` number, since 2 + 1 + 279 + 95 + 9 + 280 = 666.

It is an interprime number because it is at equal distance from previous prime (21279959263) and next prime (21279959297).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4959376 + ... + 4963664.

It is an arithmetic number, because the mean of its divisors is an integer number (458416530).

Almost surely, 2^21279959280 is an apocalyptic number.

21279959280 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 21279959280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36673322400).

21279959280 is an abundant number, since it is smaller than the sum of its proper divisors (52066685520).

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

21279959280 is a wasteful number, since it uses less digits than its factorization.

21279959280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6608 (or 6596 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 54.

The spelling of 21279959280 in words is "twenty-one billion, two hundred seventy-nine million, nine hundred fifty-nine thousand, two hundred eighty".