19902 has 16 divisors (see below), whose sum is σ = 41472. Its totient is φ = 6360.

The previous prime is 19891. The next prime is 19913. The reversal of 19902 is 20991.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (19891) and next prime (19913).

It is a congruent number.

It is an unprimeable number.

19902 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133 + ... + 239.

It is an arithmetic number, because the mean of its divisors is an integer number (2592).

2¹⁹⁹⁰² is an apocalyptic number.

19902 is an abundant number, since it is smaller than the sum of its proper divisors (21570).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20736).

19902 is a wasteful number, since it uses less digits than its factorization.

19902 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143.

The product of its (nonzero) digits is 162, while the sum is 21.

The square root of 19902 is about 141.0744484306. The cubic root of 19902 is about 27.0997680658.

Subtracting from 19902 its sum of digits (21), we obtain a square (19881 = 141²).

Subtracting 19902 from its reverse (20991), we obtain a square (1089 = 33²).

The spelling of 19902 in words is "nineteen thousand, nine hundred two".