19997280 has 120 divisors (see below), whose sum is σ = 70619472. Its totient is φ = 5329152.

The previous prime is 19997267. The next prime is 19997297. The reversal of 19997280 is 8279991.

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

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 12189 + ... + 13731.

Almost surely, 2^19997280 is an apocalyptic number.

19997280 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 19997280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35309736).

19997280 is an abundant number, since it is smaller than the sum of its proper divisors (50622192).

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

19997280 is a wasteful number, since it uses less digits than its factorization.

19997280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1570 (or 1553 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 19997280 is about 4471.8318394144. The cubic root of 19997280 is about 271.4294557417.

It can be divided in two parts, 199 and 97280, that added together give a palindrome (97479).

The spelling of 19997280 in words is "nineteen million, nine hundred ninety-seven thousand, two hundred eighty".