20911357 has 8 divisors (see below), whose sum is σ = 21255416. Its totient is φ = 20570112.

The previous prime is 20911339. The next prime is 20911403. The reversal of 20911357 is 75311902.

It can be written as a sum of positive squares in 4 ways, for example, as 63001 + 20848356 = 251^2 + 4566^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20911357 - 2¹⁹ = 20387069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20911307) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18163 + ... + 19279.

It is an arithmetic number, because the mean of its divisors is an integer number (2656927).

Almost surely, 2^20911357 is an apocalyptic number.

It is an amenable number.

20911357 is a deficient number, since it is larger than the sum of its proper divisors (344059).

20911357 is a wasteful number, since it uses less digits than its factorization.

20911357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1407.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 20911357 is about 4572.8937227974. The cubic root of 20911357 is about 275.5036807687.

The spelling of 20911357 in words is "twenty million, nine hundred eleven thousand, three hundred fifty-seven".