1977989 has 8 divisors (see below), whose sum is σ = 2161152. Its totient is φ = 1799280.

The previous prime is 1977979. The next prime is 1977991. The reversal of 1977989 is 9897791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1977989 - 2¹² = 1973893 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1977929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 149 + ... + 1994.

It is an arithmetic number, because the mean of its divisors is an integer number (270144).

2^1977989 is an apocalyptic number.

It is an amenable number.

1977989 is a deficient number, since it is larger than the sum of its proper divisors (183163).

1977989 is a wasteful number, since it uses less digits than its factorization.

1977989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2227.

The product of its digits is 285768, while the sum is 50.

The square root of 1977989 is about 1406.4099686791. The cubic root of 1977989 is about 125.5281969204.

It can be divided in two parts, 1977 and 989, that multiplied together give a triangular number (1955253 = T₁₉₇₇).

The spelling of 1977989 in words is "one million, nine hundred seventy-seven thousand, nine hundred eighty-nine".