618490721 has 4 divisors (see below), whose sum is σ = 624867012. Its totient is φ = 612114432.

The previous prime is 618490711. The next prime is 618490729. The reversal of 618490721 is 127094816.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 465696400 + 152794321 = 21580^2 + 12361^2 .

It is a cyclic number.

It is not a de Polignac number, because 618490721 - 2⁶ = 618490657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (618490729) 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, 3188000 + ... + 3188193.

It is an arithmetic number, because the mean of its divisors is an integer number (156216753).

Almost surely, 2^618490721 is an apocalyptic number.

It is an amenable number.

618490721 is a deficient number, since it is larger than the sum of its proper divisors (6376291).

618490721 is an equidigital number, since it uses as much as digits as its factorization.

618490721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6376290.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 618490721 is about 24869.4736775831. The cubic root of 618490721 is about 852.0094194151.

The spelling of 618490721 in words is "six hundred eighteen million, four hundred ninety thousand, seven hundred twenty-one".