1221535315533 has 16 divisors (see below), whose sum is σ = 1754773263936. Its totient is φ = 751382396160.

The previous prime is 1221535315489. The next prime is 1221535315549. The reversal of 1221535315533 is 3355135351221.

It is not a de Polignac number, because 1221535315533 - 2¹⁷ = 1221535184461 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 1221535315491 and 1221535315500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221535315433) 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, 6819708 + ... + 6996533.

It is an arithmetic number, because the mean of its divisors is an integer number (109673328996).

Almost surely, 2^{1221535315533} is an apocalyptic number.

1221535315533 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1221535315533 is a deficient number, since it is larger than the sum of its proper divisors (533237948403).

1221535315533 is a wasteful number, since it uses less digits than its factorization.

1221535315533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13818524.

The product of its digits is 202500, while the sum is 39.

The spelling of 1221535315533 in words is "one trillion, two hundred twenty-one billion, five hundred thirty-five million, three hundred fifteen thousand, five hundred thirty-three".