1981155434 has 4 divisors (see below), whose sum is σ = 2971733154. Its totient is φ = 990577716.

The previous prime is 1981155427. The next prime is 1981155461. The reversal of 1981155434 is 4345511891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 4345511891 = 7 ⋅620787413.

It can be written as a sum of positive squares in only one way, i.e., 1093294225 + 887861209 = 33065^2 + 29797^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1981155391 and 1981155400.

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 as a sum of consecutive naturals, namely, 495288857 + ... + 495288860.

Almost surely, 2^1981155434 is an apocalyptic number.

1981155434 is a deficient number, since it is larger than the sum of its proper divisors (990577720).

1981155434 is an equidigital number, since it uses as much as digits as its factorization.

1981155434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 990577719.

The product of its digits is 86400, while the sum is 41.

The square root of 1981155434 is about 44510.1722530929. The cubic root of 1981155434 is about 1255.9514451898.

The spelling of 1981155434 in words is "one billion, nine hundred eighty-one million, one hundred fifty-five thousand, four hundred thirty-four".