1351221005661 has 8 divisors (see below), whose sum is σ = 1809495379680. Its totient is φ = 896880317712.

The previous prime is 1351221005633. The next prime is 1351221005669. The reversal of 1351221005661 is 1665001221531.

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

It is a de Polignac number, because none of the positive numbers 2^k-1351221005661 is a prime.

It is a super-2 number, since 2×1351221005661² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1351221005669) 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, 983420715 + ... + 983422088.

It is an arithmetic number, because the mean of its divisors is an integer number (226186922460).

Almost surely, 2^{1351221005661} is an apocalyptic number.

It is an amenable number.

1351221005661 is a deficient number, since it is larger than the sum of its proper divisors (458274374019).

1351221005661 is a wasteful number, since it uses less digits than its factorization.

1351221005661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1966843035.

The product of its (nonzero) digits is 10800, while the sum is 33.

The spelling of 1351221005661 in words is "one trillion, three hundred fifty-one billion, two hundred twenty-one million, five thousand, six hundred sixty-one".