721340743 has 4 divisors (see below), whose sum is σ = 752703408. Its totient is φ = 689978080.

The previous prime is 721340729. The next prime is 721340761. The reversal of 721340743 is 347043127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 347043127 = 2531 ⋅137117.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721340743 is a prime.

It is a Smith number, since the sum of its digits (31) 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 a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721340713) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15681298 + ... + 15681343.

It is an arithmetic number, because the mean of its divisors is an integer number (188175852).

Almost surely, 2^721340743 is an apocalyptic number.

721340743 is a deficient number, since it is larger than the sum of its proper divisors (31362665).

721340743 is a wasteful number, since it uses less digits than its factorization.

721340743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31362664.

The product of its (nonzero) digits is 14112, while the sum is 31.

The square root of 721340743 is about 26857.7873809441. The cubic root of 721340743 is about 896.8369387920.

The spelling of 721340743 in words is "seven hundred twenty-one million, three hundred forty thousand, seven hundred forty-three".