821748729 has 16 divisors (see below), whose sum is σ = 1127198592. Its totient is φ = 532267008.

The previous prime is 821748701. The next prime is 821748779. The reversal of 821748729 is 927847128.

It is not a de Polignac number, because 821748729 - 2²⁷ = 687531001 is a prime.

It is a super-2 number, since 2×821748729² = 1350541947226230882, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (821748779) 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 15 ways as a sum of consecutive naturals, for example, 8712 + ... + 41465.

It is an arithmetic number, because the mean of its divisors is an integer number (70449912).

Almost surely, 2^821748729 is an apocalyptic number.

It is an amenable number.

821748729 is a deficient number, since it is larger than the sum of its proper divisors (305449863).

821748729 is a wasteful number, since it uses less digits than its factorization.

821748729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50336.

The product of its digits is 451584, while the sum is 48.

The square root of 821748729 is about 28666.1599974604. The cubic root of 821748729 is about 936.6550529554.

The spelling of 821748729 in words is "eight hundred twenty-one million, seven hundred forty-eight thousand, seven hundred twenty-nine".