1221212209977 has 16 divisors (see below), whose sum is σ = 1809278932480. Its totient is φ = 814107427056.

The previous prime is 1221212209949. The next prime is 1221212209991. The reversal of 1221212209977 is 7799022121221.

1221212209977 is a `hidden beast` number, since 1 + 221 + 212 + 209 + 9 + 7 + 7 = 666.

It is not a de Polignac number, because 1221212209977 - 2⁶ = 1221212209913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221212209927) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 279598 + ... + 1587639.

It is an arithmetic number, because the mean of its divisors is an integer number (113079933280).

Almost surely, 2^{1221212209977} is an apocalyptic number.

It is an amenable number.

1221212209977 is a deficient number, since it is larger than the sum of its proper divisors (588066722503).

1221212209977 is a wasteful number, since it uses less digits than its factorization.

1221212209977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1891469 (or 1891463 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 45.

The spelling of 1221212209977 in words is "one trillion, two hundred twenty-one billion, two hundred twelve million, two hundred nine thousand, nine hundred seventy-seven".