1981437855 has 16 divisors (see below), whose sum is σ = 3191299584. Its totient is φ = 1049767200.

The previous prime is 1981437817. The next prime is 1981437869. The reversal of 1981437855 is 5587341891.

It is not a de Polignac number, because 1981437855 - 2⁸ = 1981437599 is a prime.

It is a super-3 number, since 3×1981437855³ (a number of 29 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1981437798 and 1981437807.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 435139 + ... + 439668.

It is an arithmetic number, because the mean of its divisors is an integer number (199456224).

Almost surely, 2^1981437855 is an apocalyptic number.

1981437855 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1981437855 is a deficient number, since it is larger than the sum of its proper divisors (1209861729).

1981437855 is a wasteful number, since it uses less digits than its factorization.

1981437855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 874966.

The product of its digits is 1209600, while the sum is 51.

The square root of 1981437855 is about 44513.3446844876. The cubic root of 1981437855 is about 1256.0111225214.

The spelling of 1981437855 in words is "one billion, nine hundred eighty-one million, four hundred thirty-seven thousand, eight hundred fifty-five".