19801836 has 36 divisors (see below), whose sum is σ = 50194872. Its totient is φ = 6582144.

The previous prime is 19801823. The next prime is 19801861. The reversal of 19801836 is 63810891.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×19801836² = 784225417941792, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 19801836.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19780 + ... + 20756.

It is an arithmetic number, because the mean of its divisors is an integer number (1394302).

Almost surely, 2^19801836 is an apocalyptic number.

It is an amenable number.

19801836 is an abundant number, since it is smaller than the sum of its proper divisors (30393036).

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

19801836 is a wasteful number, since it uses less digits than its factorization.

19801836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1550 (or 1545 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 19801836 is about 4449.9253926330. The cubic root of 19801836 is about 270.5422845987.

The spelling of 19801836 in words is "nineteen million, eight hundred one thousand, eight hundred thirty-six".