721225606 has 4 divisors (see below), whose sum is σ = 1081838412. Its totient is φ = 360612802.

The previous prime is 721225591. The next prime is 721225607. The reversal of 721225606 is 606522127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 606522127 = 23747 ⋅25541.

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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (721225607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 180306400 + ... + 180306403.

It is an arithmetic number, because the mean of its divisors is an integer number (270459603).

Almost surely, 2^721225606 is an apocalyptic number.

721225606 is a deficient number, since it is larger than the sum of its proper divisors (360612806).

721225606 is a wasteful number, since it uses less digits than its factorization.

721225606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360612805.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 721225606 is about 26855.6438388656. The cubic root of 721225606 is about 896.7892199619.

The spelling of 721225606 in words is "seven hundred twenty-one million, two hundred twenty-five thousand, six hundred six".