19802 has 4 divisors (see below), whose sum is σ = 29706.
Its totient is φ = 9900.
The previous prime is 19801. The next prime is 19813. The reversal of 19802 is 20891.
Subtracting 19802 from its reverse (20891), we obtain a square (1089 = 332).
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 20891 = 13 ⋅1607.
It can be written as a sum of positive squares in only one way, i.e., 11881 + 7921 = 109^2 + 89^2
It is not an unprimeable number, because it can be changed into a prime (19801) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4949 + ... + 4952.
219802 is an apocalyptic number.
19802 is a deficient number, since it is larger than the sum of its proper divisors (9904).
19802 is an equidigital number, since it uses as much as digits as its factorization.
19802 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 9903.
The product of its (nonzero) digits is 144, while the sum is 20.
The square root of 19802 is about 140.7195793058.
The cubic root of 19802 is about 27.0543031479.
The spelling of 19802 in words is "nineteen thousand, eight hundred two".