16215640 has 64 divisors (see below), whose sum is σ = 43156800. Its totient is φ = 5365248.

The previous prime is 16215631. The next prime is 16215643. The reversal of 16215640 is 4651261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16215643) 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, 7122 + ... + 9118.

It is an arithmetic number, because the mean of its divisors is an integer number (674325).

Almost surely, 2^16215640 is an apocalyptic number.

16215640 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 16215640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21578400).

16215640 is an abundant number, since it is smaller than the sum of its proper divisors (26941160).

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

16215640 is a wasteful number, since it uses less digits than its factorization.

16215640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2044 (or 2040 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 16215640 is about 4026.8647854131. The cubic root of 16215640 is about 253.1112010971. Note that the first 3 decimals are identical.

The spelling of 16215640 in words is "sixteen million, two hundred fifteen thousand, six hundred forty".