81440701 has 4 divisors (see below), whose sum is σ = 82977372. Its totient is φ = 79904032.

The previous prime is 81440629. The next prime is 81440713. The reversal of 81440701 is 10704418.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10704418 = 2 ⋅5352209.

It can be written as a sum of positive squares in 2 ways, for example, as 19802500 + 61638201 = 4450^2 + 7851^2 .

It is a cyclic number.

It is not a de Polignac number, because 81440701 - 2⁷ = 81440573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81440101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 768256 + ... + 768361.

It is an arithmetic number, because the mean of its divisors is an integer number (20744343).

Almost surely, 2^81440701 is an apocalyptic number.

It is an amenable number.

81440701 is a deficient number, since it is larger than the sum of its proper divisors (1536671).

81440701 is a wasteful number, since it uses less digits than its factorization.

81440701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1536670.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 81440701 is about 9024.4501771576. The cubic root of 81440701 is about 433.4581446525.

The spelling of 81440701 in words is "eighty-one million, four hundred forty thousand, seven hundred one".