40643531777 has 2 divisors, whose sum is σ = 40643531778. Its totient is φ = 40643531776.

The previous prime is 40643531767. The next prime is 40643531837. The reversal of 40643531777 is 77713534604.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37868770801 + 2774760976 = 194599^2 + 52676^2 .

It is a cyclic number.

It is not a de Polignac number, because 40643531777 - 2¹² = 40643527681 is a prime.

It is not a weakly prime, because it can be changed into another prime (40643531767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20321765888 + 20321765889.

It is an arithmetic number, because the mean of its divisors is an integer number (20321765889).

Almost surely, 2^40643531777 is an apocalyptic number.

It is an amenable number.

40643531777 is a deficient number, since it is larger than the sum of its proper divisors (1).

40643531777 is an equidigital number, since it uses as much as digits as its factorization.

40643531777 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1481760, while the sum is 47.

The spelling of 40643531777 in words is "forty billion, six hundred forty-three million, five hundred thirty-one thousand, seven hundred seventy-seven".