1221536729808 has 100 divisors (see below), whose sum is σ = 3721559751360. Its totient is φ = 385748433216.

The previous prime is 1221536729761. The next prime is 1221536729837. The reversal of 1221536729808 is 8089276351221.

1221536729808 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 536 + 7 + 29 + 80 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 24779160 + ... + 24828407.

Almost surely, 2^{1221536729808} is an apocalyptic number.

1221536729808 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1221536729808 is an abundant number, since it is smaller than the sum of its proper divisors (2500023021552).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221536729808 is a wasteful number, since it uses less digits than its factorization.

1221536729808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49607606 (or 49607591 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 54.

The spelling of 1221536729808 in words is "one trillion, two hundred twenty-one billion, five hundred thirty-six million, seven hundred twenty-nine thousand, eight hundred eight".