20807691 has 4 divisors (see below), whose sum is σ = 27743592. Its totient is φ = 13871792.

The previous prime is 20807687. The next prime is 20807693. The reversal of 20807691 is 19670802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20807691 - 2² = 20807687 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20807693) 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, 3467946 + ... + 3467951.

It is an arithmetic number, because the mean of its divisors is an integer number (6935898).

Almost surely, 2^20807691 is an apocalyptic number.

20807691 is a deficient number, since it is larger than the sum of its proper divisors (6935901).

20807691 is an equidigital number, since it uses as much as digits as its factorization.

20807691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6935900.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 20807691 is about 4561.5448041206. The cubic root of 20807691 is about 275.0476655669.

The spelling of 20807691 in words is "twenty million, eight hundred seven thousand, six hundred ninety-one".