70728691 has 4 divisors (see below), whose sum is σ = 77158584. Its totient is φ = 64298800.

The previous prime is 70728667. The next prime is 70728733. The reversal of 70728691 is 19682707.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 70728691 - 2⁷ = 70728563 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (70728631) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3214930 + ... + 3214951.

It is an arithmetic number, because the mean of its divisors is an integer number (19289646).

Almost surely, 2^70728691 is an apocalyptic number.

70728691 is a deficient number, since it is larger than the sum of its proper divisors (6429893).

70728691 is a wasteful number, since it uses less digits than its factorization.

70728691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6429892.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 70728691 is about 8410.0351366686. The cubic root of 70728691 is about 413.5536645419.

The spelling of 70728691 in words is "seventy million, seven hundred twenty-eight thousand, six hundred ninety-one".