1221755216619 has 24 divisors (see below), whose sum is σ = 1896555952080. Its totient is φ = 697560536064.

The previous prime is 1221755216611. The next prime is 1221755216639. The reversal of 1221755216619 is 9166125571221.

It is not a de Polignac number, because 1221755216619 - 2³ = 1221755216611 is a prime.

It is a super-2 number, since 2×1221755216619² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221755216611) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3307974 + ... + 3658715.

It is an arithmetic number, because the mean of its divisors is an integer number (79023164670).

Almost surely, 2^{1221755216619} is an apocalyptic number.

1221755216619 is a deficient number, since it is larger than the sum of its proper divisors (674800735461).

1221755216619 is a wasteful number, since it uses less digits than its factorization.

1221755216619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6967899 (or 6967892 counting only the distinct ones).

The product of its digits is 453600, while the sum is 48.

The spelling of 1221755216619 in words is "one trillion, two hundred twenty-one billion, seven hundred fifty-five million, two hundred sixteen thousand, six hundred nineteen".