81406901 has 4 divisors (see below), whose sum is σ = 81820332. Its totient is φ = 80993472.

The previous prime is 81406889. The next prime is 81406903. The reversal of 81406901 is 10960418.

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 76562500 + 4844401 = 8750^2 + 2201^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81406901 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 (81406903) 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, 206420 + ... + 206813.

It is an arithmetic number, because the mean of its divisors is an integer number (20455083).

Almost surely, 2^81406901 is an apocalyptic number.

It is an amenable number.

81406901 is a deficient number, since it is larger than the sum of its proper divisors (413431).

81406901 is a wasteful number, since it uses less digits than its factorization.

81406901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 413430.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 81406901 is about 9022.5772925478. The cubic root of 81406901 is about 433.3981709030.

The spelling of 81406901 in words is "eighty-one million, four hundred six thousand, nine hundred one".