1227638673561 has 4 divisors (see below), whose sum is σ = 1636851564752. Its totient is φ = 818425782372.

The previous prime is 1227638673473. The next prime is 1227638673571. The reversal of 1227638673561 is 1653768367221.

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 not a de Polignac number, because 1227638673561 - 2⁷ = 1227638673433 is a prime.

It is a super-2 number, since 2×1227638673561² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1227638673571) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 204606445591 + ... + 204606445596.

It is an arithmetic number, because the mean of its divisors is an integer number (409212891188).

Almost surely, 2^{1227638673561} is an apocalyptic number.

It is an amenable number.

1227638673561 is a deficient number, since it is larger than the sum of its proper divisors (409212891191).

1227638673561 is an equidigital number, since it uses as much as digits as its factorization.

1227638673561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409212891190.

The product of its digits is 15240960, while the sum is 57.

The spelling of 1227638673561 in words is "one trillion, two hundred twenty-seven billion, six hundred thirty-eight million, six hundred seventy-three thousand, five hundred sixty-one".