721969041890 has 16 divisors (see below), whose sum is σ = 1375988056632. Its totient is φ = 271800109824.

The previous prime is 721969041851. The next prime is 721969041953. The reversal of 721969041890 is 98140969127.

It can be written as a sum of positive squares in 4 ways, for example, as 712138517689 + 9830524201 = 843883^2 + 99149^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2123438189 + ... + 2123438528.

Almost surely, 2^721969041890 is an apocalyptic number.

721969041890 is a deficient number, since it is larger than the sum of its proper divisors (654019014742).

721969041890 is a wasteful number, since it uses less digits than its factorization.

721969041890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4246876741.

The product of its (nonzero) digits is 1959552, while the sum is 56.

The spelling of 721969041890 in words is "seven hundred twenty-one billion, nine hundred sixty-nine million, forty-one thousand, eight hundred ninety".