1977266981 has 2 divisors, whose sum is σ = 1977266982. Its totient is φ = 1977266980.

The previous prime is 1977266969. The next prime is 1977266983. The reversal of 1977266981 is 1896627791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1818254881 + 159012100 = 42641^2 + 12610^2 .

It is a cyclic number.

It is not a de Polignac number, because 1977266981 - 2⁶ = 1977266917 is a prime.

It is a super-2 number, since 2×1977266981² = 7819169428305708722, which contains 22 as substring.

Together with 1977266983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1977266983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 988633490 + 988633491.

It is an arithmetic number, because the mean of its divisors is an integer number (988633491).

Almost surely, 2^1977266981 is an apocalyptic number.

It is an amenable number.

1977266981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1977266981 is an equidigital number, since it uses as much as digits as its factorization.

1977266981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 56.

The square root of 1977266981 is about 44466.4703006659. The cubic root of 1977266981 is about 1255.1292134277.

The spelling of 1977266981 in words is "one billion, nine hundred seventy-seven million, two hundred sixty-six thousand, nine hundred eighty-one".