20211613 has 2 divisors, whose sum is σ = 20211614. Its totient is φ = 20211612.

The previous prime is 20211593. The next prime is 20211617. The reversal of 20211613 is 31611202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19731364 + 480249 = 4442^2 + 693^2 .

It is a cyclic number.

It is not a de Polignac number, because 20211613 - 2²¹ = 18114461 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20211617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105806 + 10105807.

It is an arithmetic number, because the mean of its divisors is an integer number (10105807).

Almost surely, 2^20211613 is an apocalyptic number.

It is an amenable number.

20211613 is a deficient number, since it is larger than the sum of its proper divisors (1).

20211613 is an equidigital number, since it uses as much as digits as its factorization.

20211613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 20211613 is about 4495.7327545129. The cubic root of 20211613 is about 272.3957483543.

Adding to 20211613 its reverse (31611202), we get a palindrome (51822815).

The spelling of 20211613 in words is "twenty million, two hundred eleven thousand, six hundred thirteen".