16401665 has 8 divisors (see below), whose sum is σ = 22493760. Its totient is φ = 11246832.

The previous prime is 16401641. The next prime is 16401701. The reversal of 16401665 is 56610461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16401665 - 2¹⁰ = 16400641 is a prime.

It is a super-2 number, since 2×16401665² = 538029229544450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 234275 + ... + 234344.

It is an arithmetic number, because the mean of its divisors is an integer number (2811720).

Almost surely, 2^16401665 is an apocalyptic number.

It is an amenable number.

16401665 is a deficient number, since it is larger than the sum of its proper divisors (6092095).

16401665 is an equidigital number, since it uses as much as digits as its factorization.

16401665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468631.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 16401665 is about 4049.8969122683. The cubic root of 16401665 is about 254.0754162565.

The spelling of 16401665 in words is "sixteen million, four hundred one thousand, six hundred sixty-five".