77900211509 has 2 divisors, whose sum is σ = 77900211510. Its totient is φ = 77900211508.

The previous prime is 77900211479. The next prime is 77900211559. The reversal of 77900211509 is 90511200977.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77828724484 + 71487025 = 278978^2 + 8455^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77900211509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77900211559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38950105754 + 38950105755.

It is an arithmetic number, because the mean of its divisors is an integer number (38950105755).

Almost surely, 2^77900211509 is an apocalyptic number.

It is an amenable number.

77900211509 is a deficient number, since it is larger than the sum of its proper divisors (1).

77900211509 is an equidigital number, since it uses as much as digits as its factorization.

77900211509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 39690, while the sum is 41.

The spelling of 77900211509 in words is "seventy-seven billion, nine hundred million, two hundred eleven thousand, five hundred nine".