16721505 has 16 divisors (see below), whose sum is σ = 29727360. Its totient is φ = 8918064.

The previous prime is 16721479. The next prime is 16721569. The reversal of 16721505 is 50512761.

It is not a de Polignac number, because 16721505 - 2⁵ = 16721473 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61797 + ... + 62066.

It is an arithmetic number, because the mean of its divisors is an integer number (1857960).

Almost surely, 2^16721505 is an apocalyptic number.

16721505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16721505 is a deficient number, since it is larger than the sum of its proper divisors (13005855).

16721505 is a wasteful number, since it uses less digits than its factorization.

16721505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123877 (or 123871 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The square root of 16721505 is about 4089.1936858016. The cubic root of 16721505 is about 255.7163249751.

The spelling of 16721505 in words is "sixteen million, seven hundred twenty-one thousand, five hundred five".