20901091 has 2 divisors, whose sum is σ = 20901092. Its totient is φ = 20901090.

The previous prime is 20901079. The next prime is 20901107. The reversal of 20901091 is 19010902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20901091 - 2¹³ = 20892899 is a prime.

It is not a weakly prime, because it can be changed into another prime (20901071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10450545 + 10450546.

It is an arithmetic number, because the mean of its divisors is an integer number (10450546).

Almost surely, 2^20901091 is an apocalyptic number.

20901091 is a deficient number, since it is larger than the sum of its proper divisors (1).

20901091 is an equidigital number, since it uses as much as digits as its factorization.

20901091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 20901091 is about 4571.7711010067. The cubic root of 20901091 is about 275.4585891032.

Adding to 20901091 its reverse (19010902), we get a palindrome (39911993).

The spelling of 20901091 in words is "twenty million, nine hundred one thousand, ninety-one".