1981437650 has 12 divisors (see below), whose sum is σ = 3685474122. Its totient is φ = 792575040.

The previous prime is 1981437637. The next prime is 1981437691. The reversal of 1981437650 is 567341891.

It can be written as a sum of positive squares in 3 ways, for example, as 1232922769 + 748514881 = 35113^2 + 27359^2 .

It is a super-3 number, since 3×1981437650³ (a number of 29 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19814327 + ... + 19814426.

Almost surely, 2^1981437650 is an apocalyptic number.

1981437650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1981437650 is a deficient number, since it is larger than the sum of its proper divisors (1704036472).

1981437650 is a wasteful number, since it uses less digits than its factorization.

1981437650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39628765 (or 39628760 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 44.

The square root of 1981437650 is about 44513.3423818073. The cubic root of 1981437650 is about 1256.0110792057.

The spelling of 1981437650 in words is "one billion, nine hundred eighty-one million, four hundred thirty-seven thousand, six hundred fifty".