19918001 has 2 divisors, whose sum is σ = 19918002. Its totient is φ = 19918000.

The previous prime is 19917991. The next prime is 19918007. The reversal of 19918001 is 10081991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18696976 + 1221025 = 4324^2 + 1105^2 .

It is an emirp because it is prime and its reverse (10081991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19918001 - 2¹⁰ = 19916977 is a prime.

It is a super-4 number, since 4×19918001⁴ (a number of 30 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (19918007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9959000 + 9959001.

It is an arithmetic number, because the mean of its divisors is an integer number (9959001).

Almost surely, 2^19918001 is an apocalyptic number.

It is an amenable number.

19918001 is a deficient number, since it is larger than the sum of its proper divisors (1).

19918001 is an equidigital number, since it uses as much as digits as its factorization.

19918001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 19918001 is about 4462.9587719359. The cubic root of 19918001 is about 271.0702876375.

Adding to 19918001 its reverse (10081991), we get a palindrome (29999992).

The spelling of 19918001 in words is "nineteen million, nine hundred eighteen thousand, one".