1977840 has 120 divisors (see below), whose sum is σ = 6905808. Its totient is φ = 506880.

The previous prime is 1977827. The next prime is 1977863. The reversal of 1977840 is 487791.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1977795 and 1977804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29487 + ... + 29553.

2^1977840 is an apocalyptic number.

1977840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1977840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3452904).

1977840 is an abundant number, since it is smaller than the sum of its proper divisors (4927968).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1977840 is a wasteful number, since it uses less digits than its factorization.

1977840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127 (or 118 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 1977840 is about 1406.3569959296. The cubic root of 1977840 is about 125.5250448686.

The spelling of 1977840 in words is "one million, nine hundred seventy-seven thousand, eight hundred forty".