1977172920 has 96 divisors (see below), whose sum is σ = 6705223200. Its totient is φ = 504320256.

The previous prime is 1977172907. The next prime is 1977172921. The reversal of 1977172920 is 292717791.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1977172921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 111115 + ... + 127674.

It is an arithmetic number, because the mean of its divisors is an integer number (69846075).

Almost surely, 2^1977172920 is an apocalyptic number.

1977172920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1977172920 is an abundant number, since it is smaller than the sum of its proper divisors (4728050280).

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

1977172920 is a wasteful number, since it uses less digits than its factorization.

1977172920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238829 (or 238822 counting only the distinct ones).

The product of its (nonzero) digits is 111132, while the sum is 45.

The square root of 1977172920 is about 44465.4126259950. The cubic root of 1977172920 is about 1255.1093104367.

The spelling of 1977172920 in words is "one billion, nine hundred seventy-seven million, one hundred seventy-two thousand, nine hundred twenty".