1981381526 has 8 divisors (see below), whose sum is σ = 2973382104. Its totient is φ = 990254160.

The previous prime is 1981381517. The next prime is 1981381547. The reversal of 1981381526 is 6251831891.

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

It is a super-3 number, since 3×1981381526³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212600 + ... + 221723.

It is an arithmetic number, because the mean of its divisors is an integer number (371672763).

Almost surely, 2^1981381526 is an apocalyptic number.

1981381526 is a deficient number, since it is larger than the sum of its proper divisors (992000578).

1981381526 is a wasteful number, since it uses less digits than its factorization.

1981381526 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436606.

The product of its digits is 103680, while the sum is 44.

The square root of 1981381526 is about 44512.7119596189. The cubic root of 1981381526 is about 1255.9992203026. Note that the first 3 decimals are identical.

The spelling of 1981381526 in words is "one billion, nine hundred eighty-one million, three hundred eighty-one thousand, five hundred twenty-six".