20301991 has 2 divisors, whose sum is σ = 20301992. Its totient is φ = 20301990.

The previous prime is 20301949. The next prime is 20301997. The reversal of 20301991 is 19910302.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20301991 - 2¹³ = 20293799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20301997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10150995 + 10150996.

It is an arithmetic number, because the mean of its divisors is an integer number (10150996).

Almost surely, 2^20301991 is an apocalyptic number.

20301991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20301991 is an equidigital number, since it uses as much as digits as its factorization.

20301991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 20301991 is about 4505.7730746233. The cubic root of 20301991 is about 272.8011585033.

The spelling of 20301991 in words is "twenty million, three hundred one thousand, nine hundred ninety-one".