70723551721 has 9 divisors (see below), whose sum is σ = 71725327479. Its totient is φ = 69735588336.

The previous prime is 70723551671. The next prime is 70723551751. The reversal of 70723551721 is 12715532707.

The square root of 70723551721 is 265939.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 40146133225 + 30577418496 = 200365^2 + 174864^2 .

It is not a de Polignac number, because 70723551721 - 2⁹ = 70723551209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (70723551751) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 19411726 + ... + 19415368.

It is an arithmetic number, because the mean of its divisors is an integer number (7969480831).

Almost surely, 2^70723551721 is an apocalyptic number.

70723551721 is the 265939-th square number.

70723551721 is the 132970-th centered octagonal number.

It is an amenable number.

70723551721 is a deficient number, since it is larger than the sum of its proper divisors (1001775758).

70723551721 is an frugal number, since it uses more digits than its factorization.

70723551721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7432 (or 3716 counting only the distinct ones).

The product of its (nonzero) digits is 102900, while the sum is 40.

The spelling of 70723551721 in words is "seventy billion, seven hundred twenty-three million, five hundred fifty-one thousand, seven hundred twenty-one".