726236921 has 4 divisors (see below), whose sum is σ = 726954852. Its totient is φ = 725518992.

The previous prime is 726236897. The next prime is 726236947. The reversal of 726236921 is 129632627.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129632627 = 47 ⋅2758141.

It can be written as a sum of positive squares in 2 ways, for example, as 281870521 + 444366400 = 16789^2 + 21080^2 .

It is a cyclic number.

It is not a de Polignac number, because 726236921 - 2⁶ = 726236857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (726236971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 357446 + ... + 359471.

It is an arithmetic number, because the mean of its divisors is an integer number (181738713).

Almost surely, 2^726236921 is an apocalyptic number.

It is an amenable number.

726236921 is a deficient number, since it is larger than the sum of its proper divisors (717931).

726236921 is a wasteful number, since it uses less digits than its factorization.

726236921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 717930.

The product of its digits is 54432, while the sum is 38.

The square root of 726236921 is about 26948.7832934995. The cubic root of 726236921 is about 898.8614908343.

The spelling of 726236921 in words is "seven hundred twenty-six million, two hundred thirty-six thousand, nine hundred twenty-one".