1221864652787 has 2 divisors, whose sum is σ = 1221864652788. Its totient is φ = 1221864652786.

The previous prime is 1221864652751. The next prime is 1221864652807. The reversal of 1221864652787 is 7872564681221.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221864652787 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221864652487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610932326393 + 610932326394.

It is an arithmetic number, because the mean of its divisors is an integer number (610932326394).

Almost surely, 2^{1221864652787} is an apocalyptic number.

1221864652787 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221864652787 is an equidigital number, since it uses as much as digits as its factorization.

1221864652787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18063360, while the sum is 59.

The spelling of 1221864652787 in words is "one trillion, two hundred twenty-one billion, eight hundred sixty-four million, six hundred fifty-two thousand, seven hundred eighty-seven".