20631613 has 4 divisors (see below), whose sum is σ = 20736540. Its totient is φ = 20526688.

The previous prime is 20631601. The next prime is 20631617. The reversal of 20631613 is 31613602.

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 20268004 + 363609 = 4502^2 + 603^2 .

It is a cyclic number.

It is not a de Polignac number, because 20631613 - 2¹⁷ = 20500541 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 (20631617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52168 + ... + 52561.

It is an arithmetic number, because the mean of its divisors is an integer number (5184135).

Almost surely, 2^20631613 is an apocalyptic number.

It is an amenable number.

20631613 is a deficient number, since it is larger than the sum of its proper divisors (104927).

20631613 is a wasteful number, since it uses less digits than its factorization.

20631613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104926.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 20631613 is about 4542.2035401334. The cubic root of 20631613 is about 274.2696344094.

The spelling of 20631613 in words is "twenty million, six hundred thirty-one thousand, six hundred thirteen".