20091551 has 2 divisors, whose sum is σ = 20091552. Its totient is φ = 20091550.

The previous prime is 20091541. The next prime is 20091559. The reversal of 20091551 is 15519002.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20091551 - 2¹⁰ = 20090527 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20091559) 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, 10045775 + 10045776.

It is an arithmetic number, because the mean of its divisors is an integer number (10045776).

Almost surely, 2^20091551 is an apocalyptic number.

20091551 is a deficient number, since it is larger than the sum of its proper divisors (1).

20091551 is an equidigital number, since it uses as much as digits as its factorization.

20091551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 450, while the sum is 23.

The square root of 20091551 is about 4482.3599810814. The cubic root of 20091551 is about 271.8553106981.

The spelling of 20091551 in words is "twenty million, ninety-one thousand, five hundred fifty-one".