81049220744 has 8 divisors (see below), whose sum is σ = 151967288910. Its totient is φ = 40524610368.

The previous prime is 81049220743. The next prime is 81049220761. The reversal of 81049220744 is 44702294018.

It can be written as a sum of positive squares in only one way, i.e., 78029718244 + 3019502500 = 279338^2 + 54950^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (81049220743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5065576289 + ... + 5065576304.

Almost surely, 2^81049220744 is an apocalyptic number.

It is an amenable number.

81049220744 is a deficient number, since it is larger than the sum of its proper divisors (70918068166).

81049220744 is a wasteful number, since it uses less digits than its factorization.

81049220744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10131152599 (or 10131152595 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 41.

The spelling of 81049220744 in words is "eighty-one billion, forty-nine million, two hundred twenty thousand, seven hundred forty-four".