1620201613 has 4 divisors (see below), whose sum is σ = 1620345628. Its totient is φ = 1620057600.

The previous prime is 1620201607. The next prime is 1620201623. The reversal of 1620201613 is 3161020261.

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 858607204 + 761594409 = 29302^2 + 27597^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1620201613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620201623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53556 + ... + 78157.

It is an arithmetic number, because the mean of its divisors is an integer number (405086407).

Almost surely, 2^1620201613 is an apocalyptic number.

It is an amenable number.

1620201613 is a deficient number, since it is larger than the sum of its proper divisors (144015).

1620201613 is a wasteful number, since it uses less digits than its factorization.

1620201613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144014.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 1620201613 is about 40251.7280747051. The cubic root of 1620201613 is about 1174.5090118241.

Adding to 1620201613 its reverse (3161020261), we get a palindrome (4781221874).

The spelling of 1620201613 in words is "one billion, six hundred twenty million, two hundred one thousand, six hundred thirteen".