1205102251821 has 32 divisors (see below), whose sum is σ = 1767872429568. Its totient is φ = 725554805760.

The previous prime is 1205102251813. The next prime is 1205102251823. The reversal of 1205102251821 is 1281522015021.

It is not a de Polignac number, because 1205102251821 - 2³ = 1205102251813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205102251823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4904325 + ... + 5144181.

It is an arithmetic number, because the mean of its divisors is an integer number (55246013424).

Almost surely, 2^{1205102251821} is an apocalyptic number.

It is an amenable number.

1205102251821 is a deficient number, since it is larger than the sum of its proper divisors (562770177747).

1205102251821 is a wasteful number, since it uses less digits than its factorization.

1205102251821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242661.

The product of its (nonzero) digits is 3200, while the sum is 30.

Adding to 1205102251821 its reverse (1281522015021), we get a palindrome (2486624266842).

The spelling of 1205102251821 in words is "one trillion, two hundred five billion, one hundred two million, two hundred fifty-one thousand, eight hundred twenty-one".