1977578920 has 32 divisors (see below), whose sum is σ = 4454821800. Its totient is φ = 790094848.

The previous prime is 1977578917. The next prime is 1977578929. The reversal of 1977578920 is 298757791.

It can be written as a sum of positive squares in 4 ways, for example, as 1674610084 + 302968836 = 40922^2 + 17406^2 .

It is not an unprimeable number, because it can be changed into a prime (1977578929) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5436 + ... + 63124.

Almost surely, 2^1977578920 is an apocalyptic number.

1977578920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1977578920 is an abundant number, since it is smaller than the sum of its proper divisors (2477242880).

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

1977578920 is a wasteful number, since it uses less digits than its factorization.

1977578920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58557 (or 58553 counting only the distinct ones).

The product of its (nonzero) digits is 2222640, while the sum is 55.

The square root of 1977578920 is about 44469.9777377952. The cubic root of 1977578920 is about 1255.1952141530.

It can be divided in two parts, 19775789 and 20, that added together give a square (19775809 = 4447²).

The spelling of 1977578920 in words is "one billion, nine hundred seventy-seven million, five hundred seventy-eight thousand, nine hundred twenty".