1787972138 has 8 divisors (see below), whose sum is σ = 2682178788. Its totient is φ = 893912544.

The previous prime is 1787972129. The next prime is 1787972149. The reversal of 1787972138 is 8312797871.

It can be written as a sum of positive squares in 2 ways, for example, as 1031887129 + 756085009 = 32123^2 + 27497^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 1787972138.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1670 + ... + 59822.

Almost surely, 2^1787972138 is an apocalyptic number.

1787972138 is a deficient number, since it is larger than the sum of its proper divisors (894206650).

1787972138 is a wasteful number, since it uses less digits than its factorization.

1787972138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73528.

The product of its digits is 1185408, while the sum is 53.

The square root of 1787972138 is about 42284.4195656036. The cubic root of 1787972138 is about 1213.7248643011.

The spelling of 1787972138 in words is "one billion, seven hundred eighty-seven million, nine hundred seventy-two thousand, one hundred thirty-eight".