19897280 has 56 divisors (see below), whose sum is σ = 51035712. Its totient is φ = 7345152.

The previous prime is 19897279. The next prime is 19897291. The reversal of 19897280 is 8279891.

19897280 = T₄₈₇ + T₄₈₈ + ... + T₆₁₆.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 1769 + ... + 6551.

It is an arithmetic number, because the mean of its divisors is an integer number (911352).

Almost surely, 2^19897280 is an apocalyptic number.

19897280 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 19897280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25517856).

19897280 is an abundant number, since it is smaller than the sum of its proper divisors (31138432).

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

19897280 is a wasteful number, since it uses less digits than its factorization.

19897280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4813 (or 4803 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 19897280 is about 4460.6367258498. The cubic root of 19897280 is about 270.9762555051.

The spelling of 19897280 in words is "nineteen million, eight hundred ninety-seven thousand, two hundred eighty".