16720665 has 32 divisors (see below), whose sum is σ = 30334080. Its totient is φ = 7796736.

The previous prime is 16720663. The next prime is 16720667. The reversal of 16720665 is 56602761.

It is an interprime number because it is at equal distance from previous prime (16720663) and next prime (16720667).

It is not a de Polignac number, because 16720665 - 2¹ = 16720663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16720663) 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, 1449 + ... + 5961.

It is an arithmetic number, because the mean of its divisors is an integer number (947940).

Almost surely, 2^16720665 is an apocalyptic number.

16720665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16720665 is a deficient number, since it is larger than the sum of its proper divisors (13613415).

16720665 is a wasteful number, since it uses less digits than its factorization.

16720665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4553.

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 16720665 is about 4089.0909747767. The cubic root of 16720665 is about 255.7120429580.

The spelling of 16720665 in words is "sixteen million, seven hundred twenty thousand, six hundred sixty-five".