1351220557661 has 4 divisors (see below), whose sum is σ = 1455160600572. Its totient is φ = 1247280514752.

The previous prime is 1351220557651. The next prime is 1351220557667. The reversal of 1351220557661 is 1667550221531.

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

It can be written as a sum of positive squares in 2 ways, for example, as 120873733561 + 1230346824100 = 347669^2 + 1109210^2 .

It is a cyclic number.

It is not a de Polignac number, because 1351220557661 - 2¹⁴ = 1351220541277 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 (1351220557667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51970021436 + ... + 51970021461.

It is an arithmetic number, because the mean of its divisors is an integer number (363790150143).

Almost surely, 2^{1351220557661} is an apocalyptic number.

It is an amenable number.

1351220557661 is a deficient number, since it is larger than the sum of its proper divisors (103940042911).

1351220557661 is a wasteful number, since it uses less digits than its factorization.

1351220557661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103940042910.

The product of its (nonzero) digits is 378000, while the sum is 44.

The spelling of 1351220557661 in words is "one trillion, three hundred fifty-one billion, two hundred twenty million, five hundred fifty-seven thousand, six hundred sixty-one".