216540025 has 12 divisors (see below), whose sum is σ = 289164652. Its totient is φ = 159906240.

The previous prime is 216540019. The next prime is 216540029. The reversal of 216540025 is 520045612.

216540025 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 2298256 + 214241769 = 1516^2 + 14637^2 .

It is not a de Polignac number, because 216540025 - 2⁵ = 216539993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216540029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 332814 + ... + 333463.

Almost surely, 2^216540025 is an apocalyptic number.

216540025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

216540025 is a deficient number, since it is larger than the sum of its proper divisors (72624627).

216540025 is a wasteful number, since it uses less digits than its factorization.

216540025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 666300 (or 666295 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 216540025 is about 14715.2990115730. The cubic root of 216540025 is about 600.4996070207.

Adding to 216540025 its reverse (520045612), we get a palindrome (736585637).

The spelling of 216540025 in words is "two hundred sixteen million, five hundred forty thousand, twenty-five".