20520691 has 2 divisors, whose sum is σ = 20520692. Its totient is φ = 20520690.

The previous prime is 20520677. The next prime is 20520701. The reversal of 20520691 is 19602502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20520691 - 2⁵ = 20520659 is a prime.

It is not a weakly prime, because it can be changed into another prime (20520191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10260345 + 10260346.

It is an arithmetic number, because the mean of its divisors is an integer number (10260346).

Almost surely, 2^20520691 is an apocalyptic number.

20520691 is a deficient number, since it is larger than the sum of its proper divisors (1).

20520691 is an equidigital number, since it uses as much as digits as its factorization.

20520691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 20520691 is about 4529.9769315086. The cubic root of 20520691 is about 273.7772311547. Note that the first 3 decimals are identical.

The spelling of 20520691 in words is "twenty million, five hundred twenty thousand, six hundred ninety-one".