20915693 has 4 divisors (see below), whose sum is σ = 21481020. Its totient is φ = 20350368.

The previous prime is 20915689. The next prime is 20915707. The reversal of 20915693 is 39651902.

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 18550249 + 2365444 = 4307^2 + 1538^2 .

It is a cyclic number.

It is not a de Polignac number, because 20915693 - 2² = 20915689 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 (20915663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 282608 + ... + 282681.

It is an arithmetic number, because the mean of its divisors is an integer number (5370255).

Almost surely, 2^20915693 is an apocalyptic number.

It is an amenable number.

20915693 is a deficient number, since it is larger than the sum of its proper divisors (565327).

20915693 is an equidigital number, since it uses as much as digits as its factorization.

20915693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 565326.

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 20915693 is about 4573.3677962744. The cubic root of 20915693 is about 275.5227214811.

The spelling of 20915693 in words is "twenty million, nine hundred fifteen thousand, six hundred ninety-three".