1977891 has 8 divisors (see below), whose sum is σ = 2643984. Its totient is φ = 1315200.

The previous prime is 1977863. The next prime is 1977917. The reversal of 1977891 is 1987791.

It is a happy number.

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

It is not a de Polignac number, because 1977891 - 2⁶ = 1977827 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1977821) 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, 1255 + ... + 2351.

It is an arithmetic number, because the mean of its divisors is an integer number (330498).

2^1977891 is an apocalyptic number.

1977891 is a deficient number, since it is larger than the sum of its proper divisors (666093).

1977891 is a wasteful number, since it uses less digits than its factorization.

1977891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1701.

The product of its digits is 31752, while the sum is 42.

The square root of 1977891 is about 1406.3751277664. The cubic root of 1977891 is about 125.5261237766.

The spelling of 1977891 in words is "one million, nine hundred seventy-seven thousand, eight hundred ninety-one".