724040721 has 32 divisors (see below), whose sum is σ = 1088985600. Its totient is φ = 475390080.

The previous prime is 724040633. The next prime is 724040729. The reversal of 724040721 is 127040427.

It is a happy number.

It is not a de Polignac number, because 724040721 - 2¹⁰ = 724039697 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (724040729) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 881491 + ... + 882311.

It is an arithmetic number, because the mean of its divisors is an integer number (34030800).

Almost surely, 2^724040721 is an apocalyptic number.

It is an amenable number.

724040721 is a deficient number, since it is larger than the sum of its proper divisors (364944879).

724040721 is a wasteful number, since it uses less digits than its factorization.

724040721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1286 (or 1280 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 27.

The square root of 724040721 is about 26908.0047755310. The cubic root of 724040721 is about 897.9544989950.

It can be divided in two parts, 7240 and 40721, that added together give a square (47961 = 219²).

The spelling of 724040721 in words is "seven hundred twenty-four million, forty thousand, seven hundred twenty-one".