19912500 has 144 divisors (see below), whose sum is σ = 65620800. Its totient is φ = 5220000.

The previous prime is 19912499. The next prime is 19912517. The reversal of 19912500 is 521991.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 337471 + ... + 337529.

It is an arithmetic number, because the mean of its divisors is an integer number (455700).

Almost surely, 2^19912500 is an apocalyptic number.

19912500 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 19912500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32810400).

19912500 is an abundant number, since it is smaller than the sum of its proper divisors (45708300).

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

19912500 is an equidigital number, since it uses as much as digits as its factorization.

19912500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97 (or 69 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 19912500 is about 4462.3424341931. The cubic root of 19912500 is about 271.0453303982.

The spelling of 19912500 in words is "nineteen million, nine hundred twelve thousand, five hundred".