1920279987 has 32 divisors (see below), whose sum is σ = 2946447360. Its totient is φ = 1235243520.

The previous prime is 1920279967. The next prime is 1920279989. The reversal of 1920279987 is 7899720291.

It is not a de Polignac number, because 1920279987 - 2²⁰ = 1919231411 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1920279989) 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 31 ways as a sum of consecutive naturals, for example, 79443 + ... + 100755.

It is an arithmetic number, because the mean of its divisors is an integer number (92076480).

Almost surely, 2^1920279987 is an apocalyptic number.

1920279987 is a deficient number, since it is larger than the sum of its proper divisors (1026167373).

1920279987 is a wasteful number, since it uses less digits than its factorization.

1920279987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21440 (or 21434 counting only the distinct ones).

The product of its (nonzero) digits is 1143072, while the sum is 54.

The square root of 1920279987 is about 43820.9993838571. Note that the first 3 decimals coincide. The cubic root of 1920279987 is about 1242.9534150497.

Adding to 1920279987 its sum of digits (54), we get a square (1920280041 = 43821²).

The spelling of 1920279987 in words is "one billion, nine hundred twenty million, two hundred seventy-nine thousand, nine hundred eighty-seven".