1638122977 has 2 divisors, whose sum is σ = 1638122978. Its totient is φ = 1638122976.

The previous prime is 1638122947. The next prime is 1638123013. The reversal of 1638122977 is 7792218361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1633453056 + 4669921 = 40416^2 + 2161^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1638122977 is a prime.

It is not a weakly prime, because it can be changed into another prime (1638122917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819061488 + 819061489.

It is an arithmetic number, because the mean of its divisors is an integer number (819061489).

Almost surely, 2^1638122977 is an apocalyptic number.

It is an amenable number.

1638122977 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638122977 is an equidigital number, since it uses as much as digits as its factorization.

1638122977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 254016, while the sum is 46.

The square root of 1638122977 is about 40473.7319381349. The cubic root of 1638122977 is about 1178.8236330166.

The spelling of 1638122977 in words is "one billion, six hundred thirty-eight million, one hundred twenty-two thousand, nine hundred seventy-seven".