216404025 has 24 divisors (see below), whose sum is σ = 369333504. Its totient is φ = 111691200.

The previous prime is 216404021. The next prime is 216404039. The reversal of 216404025 is 520404612.

It is not a de Polignac number, because 216404025 - 2² = 216404021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 216403986 and 216404004.

It is not an unprimeable number, because it can be changed into a prime (216404021) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44214 + ... + 48863.

It is an arithmetic number, because the mean of its divisors is an integer number (15388896).

Almost surely, 2^216404025 is an apocalyptic number.

216404025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

216404025 is a deficient number, since it is larger than the sum of its proper divisors (152929479).

216404025 is a wasteful number, since it uses less digits than its factorization.

216404025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93121 (or 93116 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 216404025 is about 14710.6772447770. The cubic root of 216404025 is about 600.3738642164.

Adding to 216404025 its reverse (520404612), we get a palindrome (736808637).

It can be divided in two parts, 21 and 6404025, that added together give a palindrome (6404046).

The spelling of 216404025 in words is "two hundred sixteen million, four hundred four thousand, twenty-five".