1977816109 has 2 divisors, whose sum is σ = 1977816110. Its totient is φ = 1977816108.

The previous prime is 1977816053. The next prime is 1977816131. The reversal of 1977816109 is 9016187791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1415414884 + 562401225 = 37622^2 + 23715^2 .

It is a cyclic number.

It is not a de Polignac number, because 1977816109 - 2¹⁵ = 1977783341 is a prime.

It is a super-2 number, since 2×1977816109² = 7823513122039799762, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1977816199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 988908054 + 988908055.

It is an arithmetic number, because the mean of its divisors is an integer number (988908055).

Almost surely, 2^1977816109 is an apocalyptic number.

It is an amenable number.

1977816109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1977816109 is an equidigital number, since it uses as much as digits as its factorization.

1977816109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 190512, while the sum is 49.

The square root of 1977816109 is about 44472.6445019857. The cubic root of 1977816109 is about 1255.2453944673.

The spelling of 1977816109 in words is "one billion, nine hundred seventy-seven million, eight hundred sixteen thousand, one hundred nine".