1221262566601 has 12 divisors (see below), whose sum is σ = 1549802589840. Its totient is φ = 951633168360.

The previous prime is 1221262566581. The next prime is 1221262566607. The reversal of 1221262566601 is 1066652621221.

It is a happy number.

It is not a de Polignac number, because 1221262566601 - 2¹³ = 1221262558409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221262566607) 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, 1132896091 + ... + 1132897168.

It is an arithmetic number, because the mean of its divisors is an integer number (129150215820).

Almost surely, 2^{1221262566601} is an apocalyptic number.

1221262566601 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221262566601 is a deficient number, since it is larger than the sum of its proper divisors (328540023239).

1221262566601 is a wasteful number, since it uses less digits than its factorization.

1221262566601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2265793284 (or 2265793277 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 40.

The spelling of 1221262566601 in words is "one trillion, two hundred twenty-one billion, two hundred sixty-two million, five hundred sixty-six thousand, six hundred one".