1351220736561 has 4 divisors (see below), whose sum is σ = 1801627648752. Its totient is φ = 900813824372.

The previous prime is 1351220736539. The next prime is 1351220736583. The reversal of 1351220736561 is 1656370221531.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (1351220736539) and next prime (1351220736583).

It is a cyclic number.

It is not a de Polignac number, because 1351220736561 - 2²⁵ = 1351187182129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1351220736521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225203456091 + ... + 225203456096.

It is an arithmetic number, because the mean of its divisors is an integer number (450406912188).

Almost surely, 2^{1351220736561} is an apocalyptic number.

It is an amenable number.

1351220736561 is a deficient number, since it is larger than the sum of its proper divisors (450406912191).

1351220736561 is an equidigital number, since it uses as much as digits as its factorization.

1351220736561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450406912190.

The product of its (nonzero) digits is 226800, while the sum is 42.

The spelling of 1351220736561 in words is "one trillion, three hundred fifty-one billion, two hundred twenty million, seven hundred thirty-six thousand, five hundred sixty-one".