1261553357305 has 8 divisors (see below), whose sum is σ = 1513906860744. Its totient is φ = 1009214131200.

The previous prime is 1261553357257. The next prime is 1261553357341. The reversal of 1261553357305 is 5037533551621.

It can be written as a sum of positive squares in 4 ways, for example, as 192320839936 + 1069232517369 = 438544^2 + 1034037^2 .

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

It is not a de Polignac number, because 1261553357305 - 2¹⁹ = 1261552833017 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3373966 + ... + 3729175.

It is an arithmetic number, because the mean of its divisors is an integer number (189238357593).

Almost surely, 2^{1261553357305} is an apocalyptic number.

It is an amenable number.

1261553357305 is a deficient number, since it is larger than the sum of its proper divisors (252353503439).

1261553357305 is an equidigital number, since it uses as much as digits as its factorization.

1261553357305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7138667.

The product of its (nonzero) digits is 1417500, while the sum is 46.

The spelling of 1261553357305 in words is "one trillion, two hundred sixty-one billion, five hundred fifty-three million, three hundred fifty-seven thousand, three hundred five".