1985605139 has 4 divisors (see below), whose sum is σ = 2269263024. Its totient is φ = 1701947256.

The previous prime is 1985605123. The next prime is 1985605159. The reversal of 1985605139 is 9315065891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9315065891 = 373 ⋅24973367.

It is a cyclic number.

It is not a de Polignac number, because 1985605139 - 2⁴ = 1985605123 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1985605093 and 1985605102.

It is not an unprimeable number, because it can be changed into a prime (1985605159) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141828932 + ... + 141828945.

It is an arithmetic number, because the mean of its divisors is an integer number (567315756).

Almost surely, 2^1985605139 is an apocalyptic number.

1985605139 is a deficient number, since it is larger than the sum of its proper divisors (283657885).

1985605139 is an equidigital number, since it uses as much as digits as its factorization.

1985605139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283657884.

The product of its (nonzero) digits is 291600, while the sum is 47.

The square root of 1985605139 is about 44560.1294769214. The cubic root of 1985605139 is about 1256.8910373937.

The spelling of 1985605139 in words is "one billion, nine hundred eighty-five million, six hundred five thousand, one hundred thirty-nine".