19720836 has 72 divisors (see below), whose sum is σ = 52835328. Its totient is φ = 6192000.

The previous prime is 19720829. The next prime is 19720843. The reversal of 19720836 is 63802791.

It is an interprime number because it is at equal distance from previous prime (19720829) and next prime (19720843).

It is a super-2 number, since 2×19720836² = 777822745077792, 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 19720836.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 45541 + ... + 45971.

It is an arithmetic number, because the mean of its divisors is an integer number (733824).

Almost surely, 2^19720836 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19720836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26417664).

19720836 is an abundant number, since it is smaller than the sum of its proper divisors (33114492).

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

19720836 is a wasteful number, since it uses less digits than its factorization.

19720836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513 (or 508 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 19720836 is about 4440.8147901033. The cubic root of 19720836 is about 270.1728933800.

The spelling of 19720836 in words is "nineteen million, seven hundred twenty thousand, eight hundred thirty-six".