1221543100450 has 24 divisors (see below), whose sum is σ = 2272106882772. Its totient is φ = 488609344320.

The previous prime is 1221543100441. The next prime is 1221543100493. The reversal of 1221543100450 is 540013451221.

It can be written as a sum of positive squares in 6 ways, for example, as 731981202481 + 489561897969 = 855559^2 + 699687^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3682872 + ... + 4000828.

Almost surely, 2^{1221543100450} is an apocalyptic number.

1221543100450 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221543100450 is a deficient number, since it is larger than the sum of its proper divisors (1050563782322).

1221543100450 is a wasteful number, since it uses less digits than its factorization.

1221543100450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394806 (or 394801 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 28.

Adding to 1221543100450 its reverse (540013451221), we get a palindrome (1761556551671).

The spelling of 1221543100450 in words is "one trillion, two hundred twenty-one billion, five hundred forty-three million, one hundred thousand, four hundred fifty".