720872421 has 4 divisors (see below), whose sum is σ = 961163232. Its totient is φ = 480581612.

The previous prime is 720872389. The next prime is 720872431. The reversal of 720872421 is 124278027.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 720872421 - 2⁵ = 720872389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720872431) 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, 120145401 + ... + 120145406.

It is an arithmetic number, because the mean of its divisors is an integer number (240290808).

Almost surely, 2^720872421 is an apocalyptic number.

It is an amenable number.

720872421 is a deficient number, since it is larger than the sum of its proper divisors (240290811).

720872421 is a wasteful number, since it uses less digits than its factorization.

720872421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240290810.

The product of its (nonzero) digits is 12544, while the sum is 33.

The square root of 720872421 is about 26849.0674139718. The cubic root of 720872421 is about 896.6428098264.

The spelling of 720872421 in words is "seven hundred twenty million, eight hundred seventy-two thousand, four hundred twenty-one".