1600721 has 2 divisors, whose sum is σ = 1600722. Its totient is φ = 1600720.

The previous prime is 1600699. The next prime is 1600727. The reversal of 1600721 is 1270061.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1597696 + 3025 = 1264^2 + 55^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1600721 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1600721.

It is not a weakly prime, because it can be changed into another prime (1600727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 800360 + 800361.

It is an arithmetic number, because the mean of its divisors is an integer number (800361).

2^1600721 is an apocalyptic number.

It is an amenable number.

1600721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1600721 is an equidigital number, since it uses as much as digits as its factorization.

1600721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 1600721 is about 1265.1960322416. The cubic root of 1600721 is about 116.9782753635.

Adding to 1600721 its reverse (1270061), we get a palindrome (2870782).

The spelling of 1600721 in words is "one million, six hundred thousand, seven hundred twenty-one".