19897724 has 54 divisors (see below), whose sum is σ = 44576280. Its totient is φ = 7743120.

The previous prime is 19897699. The next prime is 19897729. The reversal of 19897724 is 42779891.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19897729) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 23297 + ... + 24135.

Almost surely, 2^19897724 is an apocalyptic number.

19897724 is a gapful number since it is divisible by the number (14) 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 19897724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22288140).

19897724 is an abundant number, since it is smaller than the sum of its proper divisors (24678556).

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

19897724 is a wasteful number, since it uses less digits than its factorization.

19897724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 879 (or 859 counting only the distinct ones).

The product of its digits is 254016, while the sum is 47.

The square root of 19897724 is about 4460.6864942518. The cubic root of 19897724 is about 270.9782710664.

The spelling of 19897724 in words is "nineteen million, eight hundred ninety-seven thousand, seven hundred twenty-four".