1981392061 has 12 divisors (see below), whose sum is σ = 2207737756. Its totient is φ = 1776582720.

The previous prime is 1981392053. The next prime is 1981392079. The reversal of 1981392061 is 1602931891.

It can be written as a sum of positive squares in 2 ways, for example, as 1528340836 + 453051225 = 39094^2 + 21285^2 .

It is not a de Polignac number, because 1981392061 - 2³ = 1981392053 is a prime.

It is a super-3 number, since 3×1981392061³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981392011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 103326 + ... + 120991.

Almost surely, 2^1981392061 is an apocalyptic number.

1981392061 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1981392061 is a deficient number, since it is larger than the sum of its proper divisors (226345695).

1981392061 is a wasteful number, since it uses less digits than its factorization.

1981392061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224412 (or 224401 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 1981392061 is about 44512.8302964437. The cubic root of 1981392061 is about 1256.0014463467.

The spelling of 1981392061 in words is "one billion, nine hundred eighty-one million, three hundred ninety-two thousand, sixty-one".