21604016207025 has 72 divisors (see below), whose sum is σ = 44243068708800. Its totient is φ = 9871657326720.

The previous prime is 21604016207021. The next prime is 21604016207069. The reversal of 21604016207025 is 52070261040612.

It is a happy number.

21604016207025 is a `hidden beast` number, since 2 + 1 + 6 + 0 + 4 + 0 + 1 + 620 + 7 + 0 + 25 = 666.

It is not a de Polignac number, because 21604016207025 - 2² = 21604016207021 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21604016207021) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 386326 + ... + 6584624.

It is an arithmetic number, because the mean of its divisors is an integer number (614487065400).

Almost surely, 2^{21604016207025} is an apocalyptic number.

21604016207025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21604016207025 is an abundant number, since it is smaller than the sum of its proper divisors (22639052501775).

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

21604016207025 is a wasteful number, since it uses less digits than its factorization.

21604016207025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6200535 (or 6200527 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

Adding to 21604016207025 its reverse (52070261040612), we get a palindrome (73674277247637).

The spelling of 21604016207025 in words is "twenty-one trillion, six hundred four billion, sixteen million, two hundred seven thousand, twenty-five".