81401806 has 4 divisors (see below), whose sum is σ = 122102712. Its totient is φ = 40700902.

The previous prime is 81401783. The next prime is 81401809. The reversal of 81401806 is 60810418.

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

It is a super-3 number, since 3×81401806³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81401809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20350450 + ... + 20350453.

It is an arithmetic number, because the mean of its divisors is an integer number (30525678).

Almost surely, 2^81401806 is an apocalyptic number.

81401806 is a deficient number, since it is larger than the sum of its proper divisors (40700906).

81401806 is a wasteful number, since it uses less digits than its factorization.

81401806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40700905.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 81401806 is about 9022.2949408673. The cubic root of 81401806 is about 433.3891290416.

The spelling of 81401806 in words is "eighty-one million, four hundred one thousand, eight hundred six".