1221550756639 has 2 divisors, whose sum is σ = 1221550756640. Its totient is φ = 1221550756638.

The previous prime is 1221550756619. The next prime is 1221550756681. The reversal of 1221550756639 is 9366570551221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221550756639 - 2¹³ = 1221550748447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221550756609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610775378319 + 610775378320.

It is an arithmetic number, because the mean of its divisors is an integer number (610775378320).

Almost surely, 2^{1221550756639} is an apocalyptic number.

1221550756639 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221550756639 is an equidigital number, since it uses as much as digits as its factorization.

1221550756639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3402000, while the sum is 52.

The spelling of 1221550756639 in words is "one trillion, two hundred twenty-one billion, five hundred fifty million, seven hundred fifty-six thousand, six hundred thirty-nine".