1977 has 4 divisors (see below), whose sum is σ = 2640. Its totient is φ = 1316.

The previous prime is 1973. The next prime is 1979. The reversal of 1977 is 7791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1977 - 2² = 1973 is a prime.

It is a D-number.

1977 is a lucky number.

It is a plaindrome in base 12 and base 15.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (1973) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 327 + ... + 332.

It is an arithmetic number, because the mean of its divisors is an integer number (660).

2¹⁹⁷⁷ is an apocalyptic number.

It is an amenable number.

1977 is a deficient number, since it is larger than the sum of its proper divisors (663).

1977 is an equidigital number, since it uses as much as digits as its factorization.

1977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662.

The product of its digits is 441, while the sum is 24.

The square root of 1977 is about 44.4634681508. The cubic root of 1977 is about 12.5507271950.

Subtracting from 1977 its sum of digits (24), we obtain a triangular number (1953 = T₆₂).

The spelling of 1977 in words is "one thousand, nine hundred seventy-seven".