20448991 has 2 divisors, whose sum is σ = 20448992. Its totient is φ = 20448990.

The previous prime is 20448949. The next prime is 20449019. The reversal of 20448991 is 19984402.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20448991 - 2¹⁹ = 19924703 is a prime.

It is a super-2 number, since 2×20448991² = 836322465836162, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20448991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20448941) 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, 10224495 + 10224496.

It is an arithmetic number, because the mean of its divisors is an integer number (10224496).

Almost surely, 2^20448991 is an apocalyptic number.

20448991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20448991 is an equidigital number, since it uses as much as digits as its factorization.

20448991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 20448991 is about 4522.0560589183. The cubic root of 20448991 is about 273.4579967068.

It can be divided in two parts, 2044899 and 1, that added together give a square (2044900 = 1430²).

The spelling of 20448991 in words is "twenty million, four hundred forty-eight thousand, nine hundred ninety-one".