721625217 has 4 divisors (see below), whose sum is σ = 962166960. Its totient is φ = 481083476.

The previous prime is 721625209. The next prime is 721625239. The reversal of 721625217 is 712526127.

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, and also an emirpimes, since its reverse is a distinct semiprime: 712526127 = 3 ⋅237508709.

It is a cyclic number.

It is not a de Polignac number, because 721625217 - 2³ = 721625209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721625257) 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, 120270867 + ... + 120270872.

It is an arithmetic number, because the mean of its divisors is an integer number (240541740).

Almost surely, 2^721625217 is an apocalyptic number.

It is an amenable number.

721625217 is a deficient number, since it is larger than the sum of its proper divisors (240541743).

721625217 is a wasteful number, since it uses less digits than its factorization.

721625217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240541742.

The product of its digits is 11760, while the sum is 33.

The square root of 721625217 is about 26863.0827903277. The cubic root of 721625217 is about 896.9548180158.

The spelling of 721625217 in words is "seven hundred twenty-one million, six hundred twenty-five thousand, two hundred seventeen".