20913645 has 16 divisors (see below), whose sum is σ = 33651072. Its totient is φ = 11090880.

The previous prime is 20913643. The next prime is 20913707. The reversal of 20913645 is 54631902.

It is not a de Polignac number, because 20913645 - 2¹ = 20913643 is a prime.

It is a super-3 number, since 3×20913645³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20913643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1137 + ... + 6566.

It is an arithmetic number, because the mean of its divisors is an integer number (2103192).

Almost surely, 2^20913645 is an apocalyptic number.

It is an amenable number.

20913645 is a deficient number, since it is larger than the sum of its proper divisors (12737427).

20913645 is a wasteful number, since it uses less digits than its factorization.

20913645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7892.

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 20913645 is about 4573.1438857749. The cubic root of 20913645 is about 275.5137284099.

The spelling of 20913645 in words is "twenty million, nine hundred thirteen thousand, six hundred forty-five".