16400400 has 120 divisors (see below), whose sum is σ = 53508480. Its totient is φ = 4293120.

The previous prime is 16400389. The next prime is 16400411. The reversal of 16400400 is 400461.

It is an interprime number because it is at equal distance from previous prime (16400389) and next prime (16400411).

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 16400400.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 94714 + ... + 94886.

It is an arithmetic number, because the mean of its divisors is an integer number (445904).

Almost surely, 2^16400400 is an apocalyptic number.

16400400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16400400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26754240).

16400400 is an abundant number, since it is smaller than the sum of its proper divisors (37108080).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16400400 is a wasteful number, since it uses less digits than its factorization.

16400400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273 (or 262 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 16400400 is about 4049.7407324420. The cubic root of 16400400 is about 254.0688841216.

Adding to 16400400 its reverse (400461), we get a palindrome (16800861).

The spelling of 16400400 in words is "sixteen million, four hundred thousand, four hundred".