1613621 has 2 divisors, whose sum is σ = 1613622. Its totient is φ = 1613620.

The previous prime is 1613609. The next prime is 1613639. The reversal of 1613621 is 1263161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1406596 + 207025 = 1186^2 + 455^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1613621 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1613593 and 1613602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1613641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 806810 + 806811.

It is an arithmetic number, because the mean of its divisors is an integer number (806811).

2^1613621 is an apocalyptic number.

It is an amenable number.

1613621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1613621 is an equidigital number, since it uses as much as digits as its factorization.

1613621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 216, while the sum is 20.

The square root of 1613621 is about 1270.2838265522. The cubic root of 1613621 is about 117.2916725014.

Adding to 1613621 its reverse (1263161), we get a palindrome (2876782).

The spelling of 1613621 in words is "one million, six hundred thirteen thousand, six hundred twenty-one".