1221726155355 has 40 divisors (see below), whose sum is σ = 2192285902752. Its totient is φ = 650924214912.

The previous prime is 1221726155333. The next prime is 1221726155359. The reversal of 1221726155355 is 5535516271221.

1221726155355 is a `hidden beast` number, since 1 + 2 + 21 + 7 + 2 + 615 + 5 + 3 + 5 + 5 = 666.

It is not a de Polignac number, because 1221726155355 - 2⁵ = 1221726155323 is a prime.

It is a super-2 number, since 2×1221726155355² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1221726155355.

It is not an unprimeable number, because it can be changed into a prime (1221726155359) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1136274 + ... + 1932503.

Almost surely, 2^{1221726155355} is an apocalyptic number.

1221726155355 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1221726155355 is a deficient number, since it is larger than the sum of its proper divisors (970559747397).

1221726155355 is an equidigital number, since it uses as much as digits as its factorization.

1221726155355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3069777 (or 3069768 counting only the distinct ones).

The product of its digits is 630000, while the sum is 45.

The spelling of 1221726155355 in words is "one trillion, two hundred twenty-one billion, seven hundred twenty-six million, one hundred fifty-five thousand, three hundred fifty-five".