20913591 has 12 divisors (see below), whose sum is σ = 28267512. Its totient is φ = 13753584.

The previous prime is 20913569. The next prime is 20913617. The reversal of 20913591 is 19531902.

It is not a de Polignac number, because 20913591 - 2⁵ = 20913559 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20913511) 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 11 ways as a sum of consecutive naturals, for example, 18165 + ... + 19281.

It is an arithmetic number, because the mean of its divisors is an integer number (2355626).

Almost surely, 2^20913591 is an apocalyptic number.

20913591 is a deficient number, since it is larger than the sum of its proper divisors (7353921).

20913591 is an equidigital number, since it uses as much as digits as its factorization.

20913591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1278 (or 1199 counting only the distinct ones).

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 20913591 is about 4573.1379817364. The cubic root of 20913591 is about 275.5134912799.

The spelling of 20913591 in words is "twenty million, nine hundred thirteen thousand, five hundred ninety-one".