1981396641 has 8 divisors (see below), whose sum is σ = 3019271104. Its totient is φ = 1132226640.

The previous prime is 1981396591. The next prime is 1981396643. The reversal of 1981396641 is 1466931891.

It is a happy number.

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

It is not a de Polignac number, because 1981396641 - 2⁶ = 1981396577 is a prime.

It is a super-3 number, since 3×1981396641³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981396643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47176090 + ... + 47176131.

It is an arithmetic number, because the mean of its divisors is an integer number (377408888).

Almost surely, 2^1981396641 is an apocalyptic number.

It is an amenable number.

1981396641 is a deficient number, since it is larger than the sum of its proper divisors (1037874463).

1981396641 is an equidigital number, since it uses as much as digits as its factorization.

1981396641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94352231.

The product of its digits is 279936, while the sum is 48.

The square root of 1981396641 is about 44512.8817422552. The cubic root of 1981396641 is about 1256.0024140977.

The spelling of 1981396641 in words is "one billion, nine hundred eighty-one million, three hundred ninety-six thousand, six hundred forty-one".