221816121025 has 24 divisors (see below), whose sum is σ = 287118658944. Its totient is φ = 169673750400.

The previous prime is 221816121017. The next prime is 221816121031. The reversal of 221816121025 is 520121618122.

It is not a de Polignac number, because 221816121025 - 2³ = 221816121017 is a prime.

It is a Duffinian number.

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, 1487677 + ... + 1629973.

It is an arithmetic number, because the mean of its divisors is an integer number (11963277456).

Almost surely, 2^221816121025 is an apocalyptic number.

221816121025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221816121025 is a deficient number, since it is larger than the sum of its proper divisors (65302537919).

221816121025 is a wasteful number, since it uses less digits than its factorization.

221816121025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145041 (or 145036 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 31.

Adding to 221816121025 its reverse (520121618122), we get a palindrome (741937739147).

The spelling of 221816121025 in words is "two hundred twenty-one billion, eight hundred sixteen million, one hundred twenty-one thousand, twenty-five".