1977609901 has 2 divisors, whose sum is σ = 1977609902. Its totient is φ = 1977609900.

The previous prime is 1977609899. The next prime is 1977609911. The reversal of 1977609901 is 1099067791.

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., 1822009225 + 155600676 = 42685^2 + 12474^2 .

It is a cyclic number.

It is not a de Polignac number, because 1977609901 - 2¹ = 1977609899 is a prime.

Together with 1977609899, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1977609911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 988804950 + 988804951.

It is an arithmetic number, because the mean of its divisors is an integer number (988804951).

Almost surely, 2^1977609901 is an apocalyptic number.

It is an amenable number.

1977609901 is a deficient number, since it is larger than the sum of its proper divisors (1).

1977609901 is an equidigital number, since it uses as much as digits as its factorization.

1977609901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 214326, while the sum is 49.

The square root of 1977609901 is about 44470.3260725621. The cubic root of 1977609901 is about 1255.2017688007.

The spelling of 1977609901 in words is "one billion, nine hundred seventy-seven million, six hundred nine thousand, nine hundred one".