20261191 has 2 divisors, whose sum is σ = 20261192. Its totient is φ = 20261190.

The previous prime is 20261179. The next prime is 20261231. The reversal of 20261191 is 19116202.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20261191 - 2⁹ = 20260679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20261291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10130595 + 10130596.

It is an arithmetic number, because the mean of its divisors is an integer number (10130596).

Almost surely, 2^20261191 is an apocalyptic number.

20261191 is a deficient number, since it is larger than the sum of its proper divisors (1).

20261191 is an equidigital number, since it uses as much as digits as its factorization.

20261191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 20261191 is about 4501.2432726970. The cubic root of 20261191 is about 272.6182905338.

Adding to 20261191 its reverse (19116202), we get a palindrome (39377393).

The spelling of 20261191 in words is "twenty million, two hundred sixty-one thousand, one hundred ninety-one".