20316691 has 4 divisors (see below), whose sum is σ = 20325712. Its totient is φ = 20307672.

The previous prime is 20316677. The next prime is 20316701. The reversal of 20316691 is 19661302.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19661302 = 2 ⋅9830651.

It is a cyclic number.

It is not a de Polignac number, because 20316691 - 2¹³ = 20308499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20316631) 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, 2026 + ... + 6688.

It is an arithmetic number, because the mean of its divisors is an integer number (5081428).

Almost surely, 2^20316691 is an apocalyptic number.

20316691 is a deficient number, since it is larger than the sum of its proper divisors (9021).

20316691 is an equidigital number, since it uses as much as digits as its factorization.

20316691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9020.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 20316691 is about 4507.4040200541. The cubic root of 20316691 is about 272.8669847162.

Adding to 20316691 its reverse (19661302), we get a palindrome (39977993).

The spelling of 20316691 in words is "twenty million, three hundred sixteen thousand, six hundred ninety-one".