19990901 has 4 divisors (see below), whose sum is σ = 22846752. Its totient is φ = 17135052.

The previous prime is 19990897. The next prime is 19990931. The reversal of 19990901 is 10909991.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19990901 - 2² = 19990897 is a prime.

It is a super-2 number, since 2×19990901² = 799272245583602, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19990931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1427915 + ... + 1427928.

It is an arithmetic number, because the mean of its divisors is an integer number (5711688).

Almost surely, 2^19990901 is an apocalyptic number.

It is an amenable number.

19990901 is a deficient number, since it is larger than the sum of its proper divisors (2855851).

19990901 is an equidigital number, since it uses as much as digits as its factorization.

19990901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2855850.

The product of its (nonzero) digits is 6561, while the sum is 38.

The square root of 19990901 is about 4471.1185401418. The cubic root of 19990901 is about 271.4005912722.

The spelling of 19990901 in words is "nineteen million, nine hundred ninety thousand, nine hundred one".