70721729 has 8 divisors (see below), whose sum is σ = 76719720. Its totient is φ = 64803456.

The previous prime is 70721719. The next prime is 70721731. The reversal of 70721729 is 92712707.

It can be written as a sum of positive squares in 4 ways, for example, as 15249025 + 55472704 = 3905^2 + 7448^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-70721729 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (70721719) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18074 + ... + 21635.

It is an arithmetic number, because the mean of its divisors is an integer number (9589965).

Almost surely, 2^70721729 is an apocalyptic number.

It is an amenable number.

70721729 is a deficient number, since it is larger than the sum of its proper divisors (5997991).

70721729 is a wasteful number, since it uses less digits than its factorization.

70721729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39859.

The product of its (nonzero) digits is 12348, while the sum is 35.

The square root of 70721729 is about 8409.6212162023. The cubic root of 70721729 is about 413.5400950599.

The spelling of 70721729 in words is "seventy million, seven hundred twenty-one thousand, seven hundred twenty-nine".