19916400 has 120 divisors (see below), whose sum is σ = 72943744. Its totient is φ = 4550400.

The previous prime is 19916399. The next prime is 19916419. The reversal of 19916400 is 461991.

It is a tau number, because it is divible by the number of its divisors (120).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7215 + ... + 9585.

Almost surely, 2^19916400 is an apocalyptic number.

19916400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19916400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36471872).

19916400 is an abundant number, since it is smaller than the sum of its proper divisors (53027344).

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

19916400 is a wasteful number, since it uses less digits than its factorization.

19916400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2399 (or 2388 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 19916400 is about 4462.7794030178. The cubic root of 19916400 is about 271.0630246067.

The spelling of 19916400 in words is "nineteen million, nine hundred sixteen thousand, four hundred".