1221780853 has 8 divisors (see below), whose sum is σ = 1252966680. Its totient is φ = 1190661120.

The previous prime is 1221780799. The next prime is 1221780869. The reversal of 1221780853 is 3580871221.

It can be written as a sum of positive squares in 4 ways, for example, as 26142769 + 1195638084 = 5113^2 + 34578^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221780853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221780893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22051 + ... + 54127.

It is an arithmetic number, because the mean of its divisors is an integer number (156620835).

Almost surely, 2^1221780853 is an apocalyptic number.

It is an amenable number.

1221780853 is a deficient number, since it is larger than the sum of its proper divisors (31185827).

1221780853 is an equidigital number, since it uses as much as digits as its factorization.

1221780853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33047.

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 1221780853 is about 34953.9819333935. The cubic root of 1221780853 is about 1069.0493938731.

The spelling of 1221780853 in words is "one billion, two hundred twenty-one million, seven hundred eighty thousand, eight hundred fifty-three".