1638143155 has 32 divisors (see below), whose sum is σ = 2236170240. Its totient is φ = 1141096320.

The previous prime is 1638143153. The next prime is 1638143173. The reversal of 1638143155 is 5513418361.

It is not a de Polignac number, because 1638143155 - 2¹ = 1638143153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1638143153) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 198522 + ... + 206608.

It is an arithmetic number, because the mean of its divisors is an integer number (69880320).

Almost surely, 2^1638143155 is an apocalyptic number.

1638143155 is a deficient number, since it is larger than the sum of its proper divisors (598027085).

1638143155 is a wasteful number, since it uses less digits than its factorization.

1638143155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8259.

The product of its digits is 43200, while the sum is 37.

The square root of 1638143155 is about 40473.9812101552. The cubic root of 1638143155 is about 1178.8284731509.

It can be divided in two parts, 16381 and 43155, that added together give a square (59536 = 244²).

The spelling of 1638143155 in words is "one billion, six hundred thirty-eight million, one hundred forty-three thousand, one hundred fifty-five".