1220612951561 has 2 divisors, whose sum is σ = 1220612951562. Its totient is φ = 1220612951560.

The previous prime is 1220612951543. The next prime is 1220612951563. The reversal of 1220612951561 is 1651592160221.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1132828150336 + 87784801225 = 1064344^2 + 296285^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220612951561 - 2²² = 1220608757257 is a prime.

It is a super-2 number, since 2×1220612951561² (a number of 25 digits) contains 22 as substring.

Together with 1220612951563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1220612951563) 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 as a sum of consecutive naturals, namely, 610306475780 + 610306475781.

It is an arithmetic number, because the mean of its divisors is an integer number (610306475781).

Almost surely, 2^{1220612951561} is an apocalyptic number.

It is an amenable number.

1220612951561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220612951561 is an equidigital number, since it uses as much as digits as its factorization.

1220612951561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64800, while the sum is 41.

The spelling of 1220612951561 in words is "one trillion, two hundred twenty billion, six hundred twelve million, nine hundred fifty-one thousand, five hundred sixty-one".