21285929247 has 8 divisors (see below), whose sum is σ = 30961351680. Its totient is φ = 12900563160.

The previous prime is 21285929243. The next prime is 21285929261. The reversal of 21285929247 is 74292958212.

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

It is not a de Polignac number, because 21285929247 - 2² = 21285929243 is a prime.

It is a super-3 number, since 3×21285929247³ (a number of 32 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21285929247.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21285929243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 322514047 + ... + 322514112.

It is an arithmetic number, because the mean of its divisors is an integer number (3870168960).

Almost surely, 2^21285929247 is an apocalyptic number.

21285929247 is a deficient number, since it is larger than the sum of its proper divisors (9675422433).

21285929247 is a wasteful number, since it uses less digits than its factorization.

21285929247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645028173.

The product of its digits is 1451520, while the sum is 51.

The spelling of 21285929247 in words is "twenty-one billion, two hundred eighty-five million, nine hundred twenty-nine thousand, two hundred forty-seven".