720958921 has 4 divisors (see below), whose sum is σ = 731113344. Its totient is φ = 710804500.

The previous prime is 720958913. The next prime is 720958961. The reversal of 720958921 is 129859027.

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 720958921 - 2³ = 720958913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720958961) 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, 5077105 + ... + 5077246.

It is an arithmetic number, because the mean of its divisors is an integer number (182778336).

Almost surely, 2^720958921 is an apocalyptic number.

720958921 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

It is an amenable number.

720958921 is a deficient number, since it is larger than the sum of its proper divisors (10154423).

720958921 is a wasteful number, since it uses less digits than its factorization.

720958921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10154422.

The product of its (nonzero) digits is 90720, while the sum is 43.

The square root of 720958921 is about 26850.6782223466. The cubic root of 720958921 is about 896.6786721597.

The spelling of 720958921 in words is "seven hundred twenty million, nine hundred fifty-eight thousand, nine hundred twenty-one".