78121789900831 has 2 divisors, whose sum is σ = 78121789900832. Its totient is φ = 78121789900830.

The previous prime is 78121789900807. The next prime is 78121789900841. The reversal of 78121789900831 is 13800998712187.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78121789900831 - 2⁷ = 78121789900703 is a prime.

It is a super-2 number, since 2×78121789900831² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78121789900841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39060894950415 + 39060894950416.

It is an arithmetic number, because the mean of its divisors is an integer number (39060894950416).

Almost surely, 2^{78121789900831} is an apocalyptic number.

78121789900831 is a deficient number, since it is larger than the sum of its proper divisors (1).

78121789900831 is an equidigital number, since it uses as much as digits as its factorization.

78121789900831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12192768, while the sum is 64.

The spelling of 78121789900831 in words is "seventy-eight trillion, one hundred twenty-one billion, seven hundred eighty-nine million, nine hundred thousand, eight hundred thirty-one".