20146991 has 2 divisors, whose sum is σ = 20146992. Its totient is φ = 20146990.

The previous prime is 20146979. The next prime is 20147021. The reversal of 20146991 is 19964102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20146991 - 2⁶ = 20146927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20146961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10073495 + 10073496.

It is an arithmetic number, because the mean of its divisors is an integer number (10073496).

Almost surely, 2^20146991 is an apocalyptic number.

20146991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20146991 is an equidigital number, since it uses as much as digits as its factorization.

20146991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 20146991 is about 4488.5399630615. The cubic root of 20146991 is about 272.1051307491.

The spelling of 20146991 in words is "twenty million, one hundred forty-six thousand, nine hundred ninety-one".