16740021 has 32 divisors (see below), whose sum is σ = 24514560. Its totient is φ = 10131264.

The previous prime is 16739993. The next prime is 16740023. The reversal of 16740021 is 12004761.

It is not a de Polignac number, because 16740021 - 2¹⁵ = 16707253 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 16740021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16740023) 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, 201646 + ... + 201728.

It is an arithmetic number, because the mean of its divisors is an integer number (766080).

Almost surely, 2^16740021 is an apocalyptic number.

It is an amenable number.

16740021 is a deficient number, since it is larger than the sum of its proper divisors (7774539).

16740021 is a wasteful number, since it uses less digits than its factorization.

16740021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 16740021 is about 4091.4570754195. The cubic root of 16740021 is about 255.8106764682.

Adding to 16740021 its reverse (12004761), we get a palindrome (28744782).

The spelling of 16740021 in words is "sixteen million, seven hundred forty thousand, twenty-one".