721860385 has 8 divisors (see below), whose sum is σ = 873898920. Its totient is φ = 572377344.

The previous prime is 721860383. The next prime is 721860401. The reversal of 721860385 is 583068127.

It can be written as a sum of positive squares in 4 ways, for example, as 91699776 + 630160609 = 9576^2 + 25103^2 .

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 721860385 - 2¹ = 721860383 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721860383) 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, 638250 + ... + 639379.

It is an arithmetic number, because the mean of its divisors is an integer number (109237365).

Almost surely, 2^721860385 is an apocalyptic number.

It is an amenable number.

721860385 is a deficient number, since it is larger than the sum of its proper divisors (152038535).

721860385 is a wasteful number, since it uses less digits than its factorization.

721860385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1277747.

The product of its (nonzero) digits is 80640, while the sum is 40.

The square root of 721860385 is about 26867.4595933445. The cubic root of 721860385 is about 897.0522426236.

The spelling of 721860385 in words is "seven hundred twenty-one million, eight hundred sixty thousand, three hundred eighty-five".