16399555 has 16 divisors (see below), whose sum is σ = 20401920. Its totient is φ = 12646368.

The previous prime is 16399541. The next prime is 16399561. The reversal of 16399555 is 55599361.

It is a cyclic number.

It is not a de Polignac number, because 16399555 - 2²¹ = 14302403 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

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, 17386 + ... + 18304.

It is an arithmetic number, because the mean of its divisors is an integer number (1275120).

Almost surely, 2^16399555 is an apocalyptic number.

16399555 is a deficient number, since it is larger than the sum of its proper divisors (4002365).

16399555 is an equidigital number, since it uses as much as digits as its factorization.

16399555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050.

The product of its digits is 182250, while the sum is 43.

The square root of 16399555 is about 4049.6364034318. The cubic root of 16399555 is about 254.0645205716.

The spelling of 16399555 in words is "sixteen million, three hundred ninety-nine thousand, five hundred fifty-five".