1238445720991 has 2 divisors, whose sum is σ = 1238445720992. Its totient is φ = 1238445720990.

The previous prime is 1238445720959. The next prime is 1238445721061. The reversal of 1238445720991 is 1990275448321.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1238445720991 - 2⁵ = 1238445720959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1238445720191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 619222860495 + 619222860496.

It is an arithmetic number, because the mean of its divisors is an integer number (619222860496).

Almost surely, 2^{1238445720991} is an apocalyptic number.

1238445720991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1238445720991 is an equidigital number, since it uses as much as digits as its factorization.

1238445720991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4354560, while the sum is 55.

The spelling of 1238445720991 in words is "one trillion, two hundred thirty-eight billion, four hundred forty-five million, seven hundred twenty thousand, nine hundred ninety-one".