21069478281 has 8 divisors (see below), whose sum is σ = 28745955040. Its totient is φ = 13719660192.

The previous prime is 21069478277. The next prime is 21069478333. The reversal of 21069478281 is 18287496012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21069478281 - 2² = 21069478277 is a prime.

It is a super-2 number, since 2×21069478281² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21069478281.

It is not an unprimeable number, because it can be changed into a prime (21069478201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81664516 + ... + 81664773.

It is an arithmetic number, because the mean of its divisors is an integer number (3593244380).

Almost surely, 2^21069478281 is an apocalyptic number.

It is an amenable number.

21069478281 is a deficient number, since it is larger than the sum of its proper divisors (7676476759).

21069478281 is a wasteful number, since it uses less digits than its factorization.

21069478281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163329335.

The product of its (nonzero) digits is 387072, while the sum is 48.

The spelling of 21069478281 in words is "twenty-one billion, sixty-nine million, four hundred seventy-eight thousand, two hundred eighty-one".