728221987 has 8 divisors (see below), whose sum is σ = 792982800. Its totient is φ = 666104544.

The previous prime is 728221981. The next prime is 728221999. The reversal of 728221987 is 789122827.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 728221987 - 2²³ = 719833379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (728221981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 660268 + ... + 661369.

It is an arithmetic number, because the mean of its divisors is an integer number (99122850).

Almost surely, 2^728221987 is an apocalyptic number.

728221987 is a deficient number, since it is larger than the sum of its proper divisors (64760813).

728221987 is a wasteful number, since it uses less digits than its factorization.

728221987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1321685.

The product of its digits is 225792, while the sum is 46.

The square root of 728221987 is about 26985.5885057191. The cubic root of 728221987 is about 899.6797160749.

The spelling of 728221987 in words is "seven hundred twenty-eight million, two hundred twenty-one thousand, nine hundred eighty-seven".