8427783509721 has 6 divisors (see below), whose sum is σ = 12173465069610. Its totient is φ = 5618522339808.

The previous prime is 8427783509707. The next prime is 8427783509729. The reversal of 8427783509721 is 1279053877248.

8427783509721 is a `hidden beast` number, since 8 + 4 + 27 + 7 + 83 + 509 + 7 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 5498931200400 + 2928852309321 = 2344980^2 + 1711389^2 .

It is not a de Polignac number, because 8427783509721 - 2⁶ = 8427783509657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8427783509729) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 468210194976 + ... + 468210194993.

It is an arithmetic number, because the mean of its divisors is an integer number (2028910844935).

Almost surely, 2^{8427783509721} is an apocalyptic number.

It is an amenable number.

8427783509721 is a deficient number, since it is larger than the sum of its proper divisors (3745681559889).

8427783509721 is a wasteful number, since it uses less digits than its factorization.

8427783509721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 936420389975 (or 936420389972 counting only the distinct ones).

The product of its (nonzero) digits is 47416320, while the sum is 63.

The spelling of 8427783509721 in words is "eight trillion, four hundred twenty-seven billion, seven hundred eighty-three million, five hundred nine thousand, seven hundred twenty-one".