81641401 has 4 divisors (see below), whose sum is σ = 81980404. Its totient is φ = 81302400.

The previous prime is 81641387. The next prime is 81641419. The reversal of 81641401 is 10414618.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 25765776 + 55875625 = 5076^2 + 7475^2 .

It is a cyclic number.

It is not a de Polignac number, because 81641401 - 2⁵ = 81641369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81641201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 169140 + ... + 169621.

It is an arithmetic number, because the mean of its divisors is an integer number (20495101).

Almost surely, 2^81641401 is an apocalyptic number.

It is an amenable number.

81641401 is a deficient number, since it is larger than the sum of its proper divisors (339003).

81641401 is a wasteful number, since it uses less digits than its factorization.

81641401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 339002.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 81641401 is about 9035.5631257825. The cubic root of 81641401 is about 433.8139196053.

The spelling of 81641401 in words is "eighty-one million, six hundred forty-one thousand, four hundred one".