721085209947 has 12 divisors (see below), whose sum is σ = 1041603064320. Its totient is φ = 480707070768.

The previous prime is 721085209919. The next prime is 721085209961. The reversal of 721085209947 is 749902580127.

721085209947 is a `hidden beast` number, since 7 + 2 + 108 + 520 + 9 + 9 + 4 + 7 = 666.

It is not a de Polignac number, because 721085209947 - 2⁶ = 721085209883 is a prime.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 721085209893 and 721085209902.

It is not an unprimeable number, because it can be changed into a prime (721085204947) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1085403 + ... + 1618724.

It is an arithmetic number, because the mean of its divisors is an integer number (86800255360).

Almost surely, 2^721085209947 is an apocalyptic number.

721085209947 is a deficient number, since it is larger than the sum of its proper divisors (320517854373).

721085209947 is a wasteful number, since it uses less digits than its factorization.

721085209947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2733762 (or 2733759 counting only the distinct ones).

The product of its (nonzero) digits is 2540160, while the sum is 54.

The spelling of 721085209947 in words is "seven hundred twenty-one billion, eighty-five million, two hundred nine thousand, nine hundred forty-seven".