81778132801 has 2 divisors, whose sum is σ = 81778132802. Its totient is φ = 81778132800.

The previous prime is 81778132789. The next prime is 81778132811. The reversal of 81778132801 is 10823187718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42199019776 + 39579113025 = 205424^2 + 198945^2 .

It is a cyclic number.

It is not a de Polignac number, because 81778132801 - 2¹³ = 81778124609 is a prime.

It is not a weakly prime, because it can be changed into another prime (81778132811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40889066400 + 40889066401.

It is an arithmetic number, because the mean of its divisors is an integer number (40889066401).

Almost surely, 2^81778132801 is an apocalyptic number.

It is an amenable number.

81778132801 is a deficient number, since it is larger than the sum of its proper divisors (1).

81778132801 is an equidigital number, since it uses as much as digits as its factorization.

81778132801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 150528, while the sum is 46.

The spelling of 81778132801 in words is "eighty-one billion, seven hundred seventy-eight million, one hundred thirty-two thousand, eight hundred one".