729375781 has 16 divisors (see below), whose sum is σ = 819878400. Its totient is φ = 645624000.

The previous prime is 729375767. The next prime is 729375791. The reversal of 729375781 is 187573927.

It is a happy number.

729375781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a 3-Lehmer number, since φ(729375781) divides (729375781-1)³.

It is a cyclic number.

It is not a de Polignac number, because 729375781 - 2²⁵ = 695821349 is a prime.

It is a super-2 number, since 2×729375781² = 1063978059818719922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (729375721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4270 + ... + 38431.

It is an arithmetic number, because the mean of its divisors is an integer number (51242400).

Almost surely, 2^729375781 is an apocalyptic number.

729375781 is the 17081-st heptagonal number.

It is an amenable number.

729375781 is a deficient number, since it is larger than the sum of its proper divisors (90502619).

729375781 is a wasteful number, since it uses less digits than its factorization.

729375781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42780.

The product of its digits is 740880, while the sum is 49.

The square root of 729375781 is about 27006.9580108534. The cubic root of 729375781 is about 900.1546158230.

The spelling of 729375781 in words is "seven hundred twenty-nine million, three hundred seventy-five thousand, seven hundred eighty-one".