1221403155535 has 4 divisors (see below), whose sum is σ = 1465683786648. Its totient is φ = 977122524424.

The previous prime is 1221403155509. The next prime is 1221403155563. The reversal of 1221403155535 is 5355513041221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221403155535 - 2⁷ = 1221403155407 is a prime.

It is a super-2 number, since 2×1221403155535² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221403155494 and 1221403155503.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122140315549 + ... + 122140315558.

It is an arithmetic number, because the mean of its divisors is an integer number (366420946662).

Almost surely, 2^{1221403155535} is an apocalyptic number.

1221403155535 is a deficient number, since it is larger than the sum of its proper divisors (244280631113).

1221403155535 is an equidigital number, since it uses as much as digits as its factorization.

1221403155535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244280631112.

The product of its (nonzero) digits is 90000, while the sum is 37.

Adding to 1221403155535 its reverse (5355513041221), we get a palindrome (6576916196756).

The spelling of 1221403155535 in words is "one trillion, two hundred twenty-one billion, four hundred three million, one hundred fifty-five thousand, five hundred thirty-five".