19981807 has 2 divisors, whose sum is σ = 19981808. Its totient is φ = 19981806.

The previous prime is 19981777. The next prime is 19981867. The reversal of 19981807 is 70818991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19981807 - 2¹¹ = 19979759 is a prime.

It is a super-2 number, since 2×19981807² = 798545221970498, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19981867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9990903 + 9990904.

It is an arithmetic number, because the mean of its divisors is an integer number (9990904).

Almost surely, 2^19981807 is an apocalyptic number.

19981807 is a deficient number, since it is larger than the sum of its proper divisors (1).

19981807 is an equidigital number, since it uses as much as digits as its factorization.

19981807 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 43.

The square root of 19981807 is about 4470.1014529874. The cubic root of 19981807 is about 271.3594310243.

The spelling of 19981807 in words is "nineteen million, nine hundred eighty-one thousand, eight hundred seven".