18897840 has 160 divisors (see below), whose sum is σ = 70203840. Its totient is φ = 4644864.

The previous prime is 18897833. The next prime is 18897847. The reversal of 18897840 is 4879881.

It is an interprime number because it is at equal distance from previous prime (18897833) and next prime (18897847).

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

It is not an unprimeable number, because it can be changed into a prime (18897847) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27744 + ... + 28416.

It is an arithmetic number, because the mean of its divisors is an integer number (438774).

Almost surely, 2^18897840 is an apocalyptic number.

18897840 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 18897840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35101920).

18897840 is an abundant number, since it is smaller than the sum of its proper divisors (51306000).

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

18897840 is a wasteful number, since it uses less digits than its factorization.

18897840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708 (or 696 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The square root of 18897840 is about 4347.1645931572. The cubic root of 18897840 is about 266.3610526619.

The spelling of 18897840 in words is "eighteen million, eight hundred ninety-seven thousand, eight hundred forty".