16815920 has 80 divisors (see below), whose sum is σ = 43309728. Its totient is φ = 6021120.

The previous prime is 16815917. The next prime is 16815923. The reversal of 16815920 is 2951861.

It is an interprime number because it is at equal distance from previous prime (16815917) and next prime (16815923).

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (16815923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 85262 + ... + 85458.

Almost surely, 2^16815920 is an apocalyptic number.

16815920 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 16815920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21654864).

16815920 is an abundant number, since it is smaller than the sum of its proper divisors (26493808).

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

16815920 is a wasteful number, since it uses less digits than its factorization.

16815920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318 (or 312 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 16815920 is about 4100.7218876681. The cubic root of 16815920 is about 256.1967075374.

The spelling of 16815920 in words is "sixteen million, eight hundred fifteen thousand, nine hundred twenty".